Midtern Exam

docx

School

Geneva College *

*We aren’t endorsed by this school

Course

502

Subject

Statistics

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by LieutenantInternet8020

Midtern Exam  Due Dec 18, 2023 at 11:59pm  Points 37  Questions 37  Available Dec 12, 2023 at 12am - Dec 18, 2023 at 11:59pm  Time Limit 180 Minutes Instructions Instructions: § This exam focuses on topics covered in lecture through and including last week § The exam is multiple choice.

§ For the multiple choice questions, choose the best answer to the questions presented. Answer all questions; there is no penalty for wrong answers. Only answers marked will be graded. § At the end of the exam, you MUST submit the exam. And you will have only one attempt to submit. Good luck! This quiz was locked Dec 18, 2023 at 11:59pm. Attempt History Attempt Time Score LATEST Attempt 1 76 minutes 24 out of 37 Score for this quiz: 24 out of 37 Submitted Dec 17, 2023 at 8:22pm This attempt took 76 minutes. Question 1 0 / 1 pts . Which of the arithmetic mean, median, and mode are resistant measures of central tendency? All the three are resistant measures The mode and arithmetic mean only. Correct Answer The median and mode only. You Answered The arithmetic mean and median only.

Question 2 1 / 1 pts > qplot(payroll,wins,col=league,shape=division) Multiple Plots Pie Charts Correct! Scatterplot Group Data by aVariable Question 3 0 / 1 pts A major videocassette rental chain is considering opening a new store in an area that currently does not have any such stores. The chain will open if there is evidence that more than 5,000 of the 20,000 households in the area are equipped with videocassette recorders (VCRs). It conducts a telephone poll of 300 randomly selected households in the area and finds that 96 have VCRs. The p-value associated with the test statistic in this problem is approximately equal to: Correct Answer 0.0026 0.0051 You Answered 0.0013

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

0.0100 Question 4 0 / 1 pts A sample of 300 subscribers to a particular magazine is selected from a population frame of 9,000 subscribers. If, upon examining the data, it is determined that no subscriber had been selected in the sample more than once, Correct Answer The sample may have been selected without replacement or with replacement. The sample could not have been random. The sample had to have been selected with replacement. You Answered The sample had to have been selected without replacement. Question 5 0 / 1 pts A simple random sample none of the above usually results in a sample that is representative of the population from which the sample was selected usually requires that a sampling frame be constructed Correct Answer

all of the above You Answered is obtained in such a way as to ensure that every member of the population has an equal chance of being selected Question 6 1 / 1 pts A Type II error is committed when We reject a null hypothesis that is false. We don't reject a null hypothesis that is true. Correct! We don't reject a null hypothesis that is false. We reject a null hypothesis that is true. Question 7 0 / 1 pts A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial aid to within 3% with 99% reliability, how many students would need to be sampled? You Answered n = 1,503 Correct Answer n = 1,784

n = 1,43 n = 1,844 Question 8 1 / 1 pts An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 hours, How large a sample is needed if we wish to be 96% confident that our sample mean will be within 10 hours of the true mean Correct! 68 67 55 None from above Question 9 0 / 1 pts Assume that a procedure yields a binomial distribution with a trial repeated n times. Use the binomial probability formula to find the probability of x successes given the probability p of success on a single trial. 13) n = 64, x = 3, p = 0.04 0.091 Correct Answer 0.221

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

0.375 You Answered 0.139 Question 10 1 / 1 pts For results based on a small random sample from a bell-shaped distribution, the distribution of the sample mean is A uniform distribution. Not a bell-shaped distribution. Correct! Approximately a normal distribution. Approximately a standard normal (z-score) distribution. Question 11 0 / 1 pts If two events are independent, then the sum of their probabilities must be equal to one. Correct Answer None of the above. they must be mutually exclusive. You Answered

their intersection must be zero. Question 12 1 / 1 pts In a winter of an epidemic flu, 2000 babies were surveyed by a well-known pharmaceutical company to determine if the company's new medicine was effective after two days. Among 120 babies who had the flu and were given the medicine, 29 were cured within two days. Among 280 babies who had the flu but were not given the medicine, 56 were cured within two days. Is there any significant indication that supports the company's claim of the effectiveness of the medicine? Correct! Fail to reject null hypothesis. There is no significant evidence to conclude that the new more effective. There is a 0.5 % chance that the null hypothesis is true. Therefore, we reject the null hypothesis. Reject null hypothesis. There is significant evidence to conclude that the new medicine is more effective. There is no enough information Question 13 0 / 1 pts In perfectly symmetrical distributions, which of the following is NOT a correct statement? The distance from the smallest observation to Q2 is the same as the distance from Q2 to the largest observation. The distance from the smallest observation to Q1 is the same as the distance from Q3 to the largest observation.

You Answered The distance from Q1 to Q2 equals to the distance from Q2 to Q3. Correct Answer The distance from Q1 to Q3 is half of the distance from the smallest to the largest observation. Question 14 0 / 1 pts In the American Heart Association journal Hypertension, researchers report that individuals who practice Transcendental Meditation (TM) lower their blood pressure significantly. If a random sample of 225 male TM practitioners meditate for 8.5 hours per week with a standard deviation of 2.25 hours, does that suggest that, on average, men who use TM meditate more than 8 hours per week? Quote a P-value in your conclusion. There is no enough information There is a 0.5 % chance that the null hypothesis is true. Therefore, we reject the null hypothesis. Correct Answer Reject null hypothesis, and conclude that the man who use MT, on average,mediate more than 8 horses par week . You Answered Fail to reject null hypothesis. There is no significant evidence to conclude that the man who use MT, on average, mediate more than 8 horses par week .. Question 15 1 / 1 pts Pick the choice that best completes the following sentence. If a relationship between two variables is called statistically significant, it means the investigators think the variables are

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

not related in the population represented by the sample. Correct! related in the population represented by the sample. very important. related in the sample due to chance alone. Question 16 1 / 1 pts Sales prices of baseball cards from the 1960s are known to possess a skewed-right distribution with a mean sale price of $5.25 and a standard deviation of $2.80. Suppose a random sample of 100 cards from the 1960s is selected. Describe the sampling distribution for the sample mean sale price of the selected cards. Skewed-right with a mean of $5.25 and a standard error of $2.80 Skewed-right with a mean of $5.25 and a standard error of $0.28 Correct! Normal with a mean of $5.25 and a standard error of $0.28 Normal with a mean of $5.25 and a standard error of $2.80 Question 17 0 / 1 pts Spinning a roulette wheel 6 times, keeping track of the occurrences of a winning number of "16". Not binomial: the trials are not independent.

Correct Answer Procedure results in a binomial distribution. Not binomial: there are too many trials. You Answered Not binomial: there are more than two outcomes for each trial. Question 18 1 / 1 pts Suppose a 95% confidence interval for µ turns out to be (1,000, 2,100). To make more useful inferences from the data, it is desired to reduce the width of the confidence interval. Which of the following will result in a reduced interval width? Correct! Increase the sample size. Increase the sample mean Increase the confidence level. Increase the population mean. Question 19 0 / 1 pts Suppose the US Department of Education is interested in knowing if the proportion of high school seniors planning on attending college is not 60%. They conduct a hypothesis test with Alpha = 0.05 and get a p-value of 0.039. What interpretation should they make?

They reject H0, and believe that the proportion of high school seniors planning to attend college is greater than 0.60. Correct Answer They reject H0, and believe that the proportion of high school seniors planning to attend college is different than 0.60. You Answered They reject H0, and believe that proportion of high school seniors planning to attend college is less than 0.6. They do not reject H0, and believe that the proportion of high school seniors planning to attend college is different than 0.60. They do not reject H0, and believe that the proportion of high school seniors planning to attend college is 0.60. Question 20 0 / 1 pts Suppose you are testing H0 : p = 0.25 vs. HA : p > 0.25. The resulting p- value is 0.306. What is your conclusion? Since the significance level, Alpha, is not given, we cannot conclude anything. Correct Answer Since the p-value, 0.306, is NOT less than even 0.10, we fail to reject at the 10% level and conclude that there is insufficient evidence to say that the true proportion, p > 0.25. Since the p-value, 0.25, is NOT less than even 0.10, we fail to reject at the 10% level and conclude that there is insufficient evidence to say that the true proportion, p > 0.306.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Since the p-value, 0.306, is NOT less than 0.25, we fail to reject at the 25% level and conclude that there is sufficient evidence to say that the true proportion, p > 0.25. You Answered Since the p-value, 0.306, is greater than 0.25, we reject and conclude that there is sufficient evidence to say that the true proportion, p > 0.25. Question 21 1 / 1 pts The Central Limit Theorem is important in statistics because Correct! For a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population. for any sized sample, it says the sampling distribution of the sample mean is approximately normal For any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size. For a large n, it says the population is approximately normal. Question 22 1 / 1 pts The classification of student class designation (freshman, sophomore, junior, senior) is an example of a discrete random variable. a parameter. a continuous random variable.

Correct! a categorical random variable. Question 23 1 / 1 pts The Dean of Students mailed a survey to a total of 400 students. The sample included 100 students randomly selected from each of the freshman, sophomore, junior, and senior classes on campus last term. What sampling method was used? Systematic sample Cluster sample Correct! Stratified sample Simple random sample Question 24 1 / 1 pts The evening host of a dinner dance reached into a bowl, mixed all the tickets around, and selected the ticket to award the grand door prize. What sampling method was used? Cluster sample Systematic sample Stratified sample

Correct! Simple random sample Question 25 1 / 1 pts The marketing manager for an automobile manufacturer is interested in determining the proportion of new compact-car owners who would have purchased a passengerside inflatable air bag if it had been available for an additional cost of $300. The manager believes from previous information that the proportion is 0.30. Suppose that a survey of 200 new compact-car owners is selected and 79 indicate that they would have purchased the inflatable air bags. If you were to conduct a test to determine whether there is evidence that the proportion is different from 0.30 and decided not to reject the null hypothesis, what conclusion could you draw? There is sufficient evidence that the proportion is 0.35. There is sufficient evidence that the proportion is 0.30. There is not sufficient evidence that the proportion is 0.35. Correct! There is not sufficient evidence that the proportion is not 0.30. Question 26 1 / 1 pts The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. Suppose she found that the sample mean was 30.45 years and the sample standard deviation was 5 years. If she wants to be 99% confident in her decision, what decision should she make? There is sufficient evidence that the mean age of her customers is over 30.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

There is not sufficient evidence that the mean age of her customers is not over 30. Correct! There is not sufficient evidence that the mean age of her customers is over 30. There is sufficient evidence that the mean age of her customers is not over 30 Question 27 1 / 1 pts When a customer enters a store there are three outcomes that can occur: buy nothing, buy a small amount, or buy a large amount. In this situation, if a customer buys a large amount, he or she cannot also buy a small amount or buy nothing. Thus the events are: Dependent events. All inclusive. Independent. Correct! Mutually exclusive. Question 28 1 / 1 pts Which of the following describes the relationship between the Central Limit Theorem and the Rule for Sample Proportions?

There is no relationship because the Central Limit Theorem is about means and the Rule for Sample Proportions is about proportions. The Central Limit Theorem is a special case of the Rule for Sample Proportions. The Central Limit Theorem is just a restatement of the Rule for Sample Proportions. Correct! The Rule for Sample Proportions follows from the Central Limit Theorem by defining each observation in the sample to be either 1 or 0. Question 29 1 / 1 pts Which of the following is a discrete quantitative variable? The distance you drove yesterday. The volume of water released from a dam Correct! The number of employees of an insurance company The Dow Jones Industrial average Question 30 1 / 1 pts Which of the following is NOT sensitive to extreme values? The range.

The standard deviation. The coefficient of variation Correct! The interquartile range. Question 31 1 / 1 pts Which of the following is true about the sampling distribution of the sample mean? The standard deviation of the sampling distribution is always sigma. None from the Above Correct! The mean of the sampling distribution is always Mu. The shape of the sampling distribution is always approximately normal. Question 32 1 / 1 pts Which of the following is true regarding the sampling distribution of the mean for a large sample size? It has a normal distribution with the same mean and standard deviation as the population. It has the same shape, mean, and standard deviation as the population.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

It has the same shape and mean as the population, but has a smaller standard deviation. Correct! It has a normal distribution with the same mean as the population but with a smaller standard deviation. Question 33 1 / 1 pts Which of the following statements about the median is not true? Correct! It is more affected by extreme values than the arithmetic mean. It is equal to the mode in bell-shaped "normal" distributions It is equal to Q2. It is a measure of central tendency. Question 34 1 / 1 pts Which of the following would indicate that a dataset is skewed to the right? The interquartile range is larger than the range. Correct! The mean is much larger than the median. The range is larger than the interquartile range. The mean is much smaller than the median.

Question 35 0 / 1 pts Which one of the following statements is false? Correct Answer The sampling distribution of any statistic becomes approximately normal for large sample sizes. The standard deviation of the sample mean decreases as the sample size increases. You Answered The sampling distribution of the sample mean is exactly normal if the observations are normally distributed. The sampling distribution of the sample mean becomes approximately normal for large sample sizes. Question 36 1 / 1 pts Which one of the following variables is not categorical: The gender of a person: male or female The marital status of a person: single, married, divorced, other. The choice on a test item: true or false. Correct! The age in years of a person.

Question 37 1 / 1 pts Why is the Central Limit Theorem so important to the study of sampling distributions? It allows us to disregard the size of the population we are sampling from. Correct! It allows us to disregard the shape of the population when the sample size is large It allows us to disregard the shape of the sampling distribution when the size of the population is large. It allows us to disregard the size of the sample selected when the population is not normal. Quiz Score: 24 out of 37

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Midtern Exam

Related Documents