2. Psychologists found the effects of preschool childcare on the development of young children.They suggest that children who spend more time away from their motheTs are more likely toshow behavioral problems. The average rating of behavioral problems for young children is u =35 and the population is normally distributed. A sample of n = 16 young children who had spentat least 20 hours per week in childcare during the previous year produced a mean score of M =42.7 with a SS= 540. The higher score indicates that a child has more behavioral problems. UseQ=.01a. Are the data sufficient to conclude that children with a history of childcare showsignificantly more behavioral problem than the average child?b. Find the 95% confidence interval.

State the hypotheses That is, there is no sufficient evidence to conclude that children with a…

Answered: 2. Psychologists found the effects of…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Belsky, Weinrub, Owen and Kelly (2001) reported on the effects of preschool child care on the development of young children. One result suggests that children who spend more time away from their mothers are more likely to show behavioral problems in kindergarten. Using a standardized scale, the average rating of behavioural problems for kindergarten children is u=35. A sample og n=16 kindergarten children who had spent at least 20 hours per week in child care during the previous year produce a mean score of 42.7 with a standard deviation of s=6. Using a one-tailed test with alpha level of 0.01, what is your critical t value? О а. 2.260 O b. 2.600 О с. 2.602 O d. 2.620 е. 2.026
2. In studying the effect of a drug for treating patients with respiratory problems, a researcher obtained a sample of 12 consenting patients, who, after discussion with their doctor, chose a respiratory drug they would receive. Patients' respiratory tests were assessed twice over a two-month period after initiating the treatment. Research question: The researcher wants to know if there is a significant difference between the group in their second test and those that didn't take the drug in their overall mean of 3.35 in average respiratory scores with a standard deviation of .08. Is there a difference between the two means - does the drug work? Carry out 9 steps of hypothesis testing. Respiratory Test 2 3.4 3.4 3.3 3.4 3.3 3.3 3.3 3.2 3.2 3.2 3.2 3.3 Σ-39.5
Is the proportion of wildfires caused by humans in the south higher than the proportion of wildfires caused by humans in the west? 408 of the 536 randomly selected wildfires looked at in the south were caused by humans while 393 of the 579 randomly selected wildfires looked at the west were caused by humans. What can be concluded at the = 0.01 level of significance? For this study, we should use Select an answer t-test for a population mean t-test for the difference between two independent population means t-test for the difference between two dependent population means z-test for a population proportion z-test for the difference between two population proportions The null and alternative hypotheses would be: Select an answer μ1 p1 Select an answer > ≠ < = Select an answer p2 μ2 (please enter a decimal) Select an answer μ1 p1 Select an answer < > ≠ = Select an answer μ2 p2 (Please enter a decimal) The test statistic ? t z = (please show your…
1. Metal Tags on Penguins and Length of Foraging Trips. Data were collected over a 10-year timespan from a sample of penguins that were randomly given either metal or electronic tags. One variable examined is the length of foraging trips. Longer foraging trips can jeopardize both breeding success and survival of chicks waiting for food. From a sample of 344 foraging trips for metal-tagged penguins, the mean length was 12.70 days. From a sample of 512 foraging trips for electronic-tagged penguins, mean length was 11.60 days. Test whether foraging trips are longer on average among metal-tagged penguins than among electronic-tagged penguins. a. State hypotheses in terms of two means. b. Calculate the sample statistic XM - XE c. An estimate of the standard error for this difference of means is SE-0.2834. Calculate a test statistic to two decimal places. d. What is the correct theoretical distribution for this test? ☐Normal ☐t with degrees of freedom e. Find the p-value and draw a…
A graduate student is interested in how viewing different types of scenes affects working memory. For his study, he selects a random sample of 36 adults. The subjects complete a series of working memory tests before and after walking in an urban setting. Before the walk, the mean score on the test of working memory was 9.1. After the walk, the mean score was 1.4 higher. The graduate student has no presupposed assumptions about how viewing different types of scenes affects working memory, so he formulates the null and alternative hypotheses as: H00 : μDD = 0 H11 : μDD ≠ 0 Assume that the data satisfy all of the required assumptions for a repeated-measures t test. The graduate student calculates the following statistics for his hypothesis test: Mean difference (MDD) 1.4 Estimated population standard deviation of the differences (s) 1.6 Estimated standard error of the mean differences (sMDMD) 0.2667 Degrees of freedom (df) 35 The t statistic 5.25 The critical values of t…
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Suppose a neighborhood has few very expensive homes and many low value homes. Which measure of central tendency a. would give the highest "average"? Why? b. would give the lowest "average"? Why? c. would be the most representative "average"? Why?
A cruise ship charges passengers $3 for a can of soda. Because of passenger complaints, the ship manager has decided to try out a plan with a lower price. He thinks that with a lower price, more cans will be sold, which would mean that the ship would still make a reasonable total profit. With the old pricing, the mean number of cans sold per passenger for a 10-day trip was 10.3 cans. Suppose μ represents the mean number of cans per passenger for the new pricing. What hypotheses should the ship manager test if he wants to determine if the mean number of cans sold is greater for the new pricing plan? O Ho: μ = 10.3 versus H₂: μ> 10.3 O Ho: μ = O Ho: μ = 10 versus Ha: μ 10.3
A school had a lot of problems with student absences and wanted to try a intervention program to see if it encouraged students to come to school more often. As a trial, 26 students were split into two equal size groups. Group 1 would get the new intervention and Group 2 got no intervention. The mean- number of absences was calculated after one month for each group, as shown in the table below. What inference can be made about the results? Group 1 Group 2 3 5 3 1 3 2 3 4 1 3 2 1 2 3 3 4 2 5 1 3 1 6 4 2 1 2 Mean: 2.2 Mean: 3.2 Frequency200 Simulated Group Mean Differences Since the simulation shows FEW CASES OR Many Cases. where a mean difference of ___ or less occurred when the groups were re-randomized, it can be inferred that the mean difference observed in the study was VERY POSSIBLY OR VERY UNLIKELY due to the random assignment of participants into groups, so the results…
According to previous studies, the mean distance each visitor in Greenspan National Park hikes during their visit is 30 kilometers. The park recently closed its shuttle system, which used to transport hikers to many of the park's most popular hiking trails. Because of this, an administrator at the park suspects the mean distance, u, is now less than 30 kilometers. The administrator chooses a random sample of 45 visitors. The mean distance hiked for the sample is 27.2 kilometers. Assume the population standard deviation is 9.9 kilometers. Can the administrator conclude that the mean distance hiked by each visitor is now less than 30 kilometers? Perform a hypothesis test, using the 0.10 level of significance. (a) State the null hypothesis H, and the alternative hYpothesis H,. O
. Justin wants to know whether a commonly prescribed drug does improve the attention span of students with attention deficit disorder (ADD). He knows that the mean attention span for students with ADD who are not taking the drug is 2.3 minutes long. His sample of 12 students taking the drug yielded a mean of 4.6 minutes. Justin can find no information regarding σx , so he calculated s2x =1.96. a. Identify the independent and dependent variables. b. In a sentence, state the null hypothesis being tested. c. Using symbols, state the null and alternative hypotheses. d. Determine the critical region using a one-tailed test with alpha = .05. e .Conduct the hypothesis test (Do the math and compare the t-critical and t-obtained values). f. State your conclusions in terms of H0 (Should you reject the H0 or fail to reject/accept the H0). g. Based on your analysis, is there a relationship between the drug and attention span?

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