Understanding Sampling Methods and Statistical Concepts in MGMT 650

Attempt Score 100 / 100 - 10 0 % Overall Grade (Highest Attempt) 100 / 100 - 10 0 % Question 1 8 / 8 points Match terms and descriptions __ Unbiased Sample __ Standard Error __ Sampling Error __ Standard Deviation __ Biased Statistic __ Random Sampling __ Biased Sample __ Convenience Sampling 1 . A sample that is representative of a population 2 . Value quantifying the spread about the mean of numeric values 3 . The standard deviation of a distribution of statistics resulting from sampling or an estimate of the standard deviation 4 . A method of sampling where each member of the population is equally likely to be included in a sample 5 . A method of sampling where easily accessible members of a population are sampled 6 . The difference between observations in a sample and observations in the population 7 . A sample obtained by a non- random sampling method 8 . The mean of a distribution of statistics is not equal to the parameter the statistic estimates tion 2 2 / po Sampling error can be eliminated by:

Obtaining an unbiased sample Performing a census Using a probability sampling method Increasing sample size View question 2 feedback Question 3 4 / 4 points Select all which are biased sampling methods Survey the first 20 people entering a particular coffee store on the last Tuesday before the next election Telephone survey Groups are selected by random sampling. People in the selected groups are surveyed. Survey two union workers for each non-union worker With each group composed of people with the same characteristic and each person belonging to only one group, a random sample is taken from each group. View question 3 feedback Question 4 5 / 5 points Match __ Systematic Random Sampling __ Stratified Random Sampling __ Cluster Random Sampling __ Simple Random Sampling __ Probability Sampling Methods 1 . Each member of the population has an equal chance of being selected for a sample. 2 . Each member of the population is assigned a unique number. Randomly select numbers from a list of assigned numbers. 3 . Each member of the population is assigned a unique number. The first number is selected randomly.

The remaining numbers are selected at equal intervals. 4 . The population is divided into separate physical units. Each member of the population belongs to only one physical unit. Physical units are selected by simple random sampling. In each of the selected units, all the members are surveyed. 5 . Each member belongs to only one unit of the same characteristic. A simple random sample of equal size is taken from each unit. tion 5 2 / po Statistical methods that assume the Normal probability distribution can be applied to processes whose data have a skew between -0.5 and +0.5, and a histogram that is roughly bell shaped. True False Questio n 6 4 / 4 points Select ALL true statements. The Normal distribution is important because many processes are approximated by the Normal distribution, and many statistical procedures assume that the data are normally distributed. The mean of a standardized normally distributed random variable is 0 and the standard deviation is 1. The Normal probability distribution curve is bell shaped. The standard normal probability distribution is applicable to the standardized value of a normal random variable = (value - mean)/sd, which is the number of standard deviations (sd) from the mean.

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The mean the normal distribution is 0 and the standard deviation is 1. Questio n 7 5 / 5 points Match Excel functions and descriptions __ NORM.S.DIST __ NORM.S.INV __ NORM.DIST __ NORM.INV __ STANDARDIZE 1 . Compute a Z-score from a value of a normal random variable, mean, and standard deviation. 2 . Compute the left-tail probability from a Z-score, and additional input 1 (0=height of curve, 1=area under curve). 3 . Compute the Z-score from a left-tail probability. 4 . Compute the left-tail probability from a value of a normal random variable, mean, standard deviation, and additional input 1 (0=height of curve, 1=area under curve). 5 . Compute the value of a normal random variable from a left-tail probability, mean, and standard deviation. tion 8 2 / po The probability distribution of the means of large samples taken from the same probability distribution will be approximately Normal regardless of the distribution the sample was taken from. This is called the Normal Distribution Theorem Central Limit Theorem

Law of Large Sample Size Law of Averages Law of Large Numbers Questio n 9 4 / 4 points Select the true statements. Distributions of sample means become approximately normally distributed when sample size is at least 50 for highly skewed populations. Distributions of sample means are approximately normally distributed because the sample mean estimates the population mean. Distributions of sample means become approximately normally distributed when sample size is at least 30 for most populations. View question 9 feedback Question 10 4 / 4 points Match formulas __ Sample Standard Deviation __ Estimated Standard Error of Sample Proportions using sample proportion p as estimate of the population proportion __ Estimated Standard Error of Sample Means __ Sample Mean 1 . 2 . 3 . 4 . tion 11 6 / po According to the Empirical Rule what percent of the population is more than 2 standard deviations away from the mean? 32% 0.3% None of the answers match my calculation.

68% 5% 95% 99.7 View question 11 feedback Question 12 6 / 6 points According to the Empirical Rule what percent of the population is above 2 standard deviation above the mean, which is a right-tail probability? 0.15% None of the answers match my calculation. 16% 97.35% 2.3% 83.85% 81.5% View question 12 feedback Question 13 6 / 6 points What is the Z score where 99.0% of the normal distribution is below that z score and 1.0% of the normal distribution lies above that same z score? 2.33 1.28 0.67 0.39 0.00 None of the answers match my calculation.

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1.64 View question 13 feedback Question 14 6 / 6 points The Z values of the limits of the area covering the middle 30.0% of the area under the normal curve are plus and minus 0.39 0.51 0.35 0.43 None of the answers match my calculation. 0.32 0.47 View question 14 feedback Question 15 6 / 6 points If the mean annual return for common stocks is 10.5% and the standard deviation 12.5%, what is the probability that the stock returns are greater than 8.0%? 47% 40% None of the answers match my calculation. 58% 0% 15% 53% View question 15 feedback Question 16 6 / 6 points

The distribution of a product is unimodal and roughly symmetric. The package is labeled 10 oz. If the standard deviation is 0.2 ounces, what should the process mean be if 2% of the product is underweight? 10.41 15.35 14.38 11.38 13.41 12.35 None of the answers match my calculation. View question 16 feedback Question 17 6 / 6 points If the mean annual return for a stock is 13%, what is the risk (standard deviation) you would take for a probability of 31% of a return being at least 17%? 17% 6% 21% 11% 8% None of the answers match my calculation. 14% View question 17 feedback Question 18 6 / 6 points The Chunkiest cookie factory changed their manufacturing process. The inspectors sampled 70 12.0-oz packages with mean 12.03 oz and a standard deviation of 1.5 oz. The CEO asks what is the upper weight boundary of the middle 55% of package weights.

9.87 13.16 None of the answers match my calculation. 12.1 10.64 8.82 14.69 View question 18 feedback Question 19 6 / 6 points If the sample standard deviation is 4.86, what would be the estimated standard error of sample means for sample size 30? Write the result with 2 decimal places. Answer: 0.89 View question 19 feedback Question 20 6 / 6 points The sample proportion is 0.50. What is the estimated standard error of the sampling distribution of sample proportions for sample of size 20? Answer: 0.11 2

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MGMT 650 Quiz 5

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