In a study on the effects stress on behaviour in rats, 78 rats
were randomly assigned to either a stressful environment or a
control (non-stressful) environment.
After 21 days, the change in weight (in grams) was determined for
each rat.
The following table summarises the data on weight gain:
n | sample mean | sample standard deviation | |
Stress | 23 | 21.08 | 13.49 |
No stress | 55 | 28.14 | 15.39 |
1.2 (1 mark)
Calculate the value of the t-statistic to three decimal places |
1.3 (.6 marks)
Using the simple method, how many degrees of freedom df does
this t-statistic have? |
1.4 (1 mark)
Calculate the p-value to three decimal places. |
1.6 (2 marks)
Now we require you to calculate a (1 − α) ×100 = 99% confidence
interval for the true mean difference between μ1 and
μ2.
1.6.1 (1 mark)
|
1.6.2 (1 mark)
Enter the confidence interval (lo, hi), where lo and hi are the
lower and upper limits, respectively, to three decimal places.
|
1.7 (.2 marks)
|
In a study on the effects stress on behaviour in rats, 78 rats were randomly assigned...
Question 1 (6.0 marks) 1 Validate Mark Unfocus Help Be aware that some information that may appear to be missing may have gone far to the right on your screen In a study on the effects stress on behaviour in rats, 76 rats were randomly assigned to either a stressful environment or a control (non-stressful) environment. After 21 days, the change in weight in grams) was determined for each rat. The following table summarises the data on weight gain: ple...
When estimating a multiple linear regression model based on 30 observations, the following results were obtained. [You may find it useful to reference the t table.] Coefficients Standard Error t Stat p-value Intercept 151.03 128.84 1.172 0.251 x1 11.42 2.67 4.277 0.000 x2 2.00 2.02 0.990 0.330 b-1. What is the 95% confidence interval for β2? (Negative values should be indicated by a minus sign. Round "tα/2,df" value to 3 decimal places, and final answers to 2 decimal places.) c-2....
Chapter 05.2 Exercise Question 21 5.2.21 A 2013 Gallup poll asked randomly selected U.S. adults whether they wanted to stay at their current body weight or change. One purpose was to investigate whether there was any difference between men and women with regard to this aspect. Of the 562 men surveyed, 242 wanted to stay at their current weight, whereas of the 477 women surveyed, 172 wanted to stay at their current weight. Use an appropriate randomization-based applet to find a p-value. Round...
section 10.3 Provided below are summary statistics for independent simple random samples from two populations. Use the nonpooled t-test and the nonpooled t-interval procedure to conduct the required hypothesis test and obtain the specified confidence interval. *4 = 10,5 - 2, 0, -20, 72 - 11,5 - 5, n2 - 20 a. Two-tailed test, a = 0.01 b. 99% confidence interval a. What are the hypotheses for the t-test? O A HOHH2 H₂H12 Oc. Ho: H = 12 Hai H1...
A researcher at a medical college conducted a study of 60 randomly selected male soccer players and concluded that frequently "heading" the ball in soccer lowers players' IQs. The soccer players were divided into two groups, based on whether they averaged 10 or more headers per game. Mean IQs were reported in the article, but the sample sizes and standard deviations were not given. Suppose that these values were as given in the accompanying table. n Sample Mean Sample sd...
An article reported on the results of an experiment in which half of the individuals in a group of 70 postmenopausal overweight women were randomly assigned to a particular vegan diet, and the other half received a diet based on National Cholesterol Education Program guidelines. The sample mean decrease in body weight for those on the vegan diet was 5.7 kg, and the sample SD was 3.5, whereas for those on the control diet, the sample mean weight loss and...
The mean number of sick days an employee takes per year is believed to be about 10. Members of a personnel department do not believe this figure. They randomly survey 8 employees. The number of sick days they took for the past year are as follows: 10; 5;15; 5; 11; 10; 8; 10. Let x the number of sick days they took for the past year. Should the personnel team believe that the mean number is about 10? Conduct a...
Two samples are randomly selected from each population. The sample statistics are given below. Find the P-value used to test the claim that H, H2. Use c = 0.05. ng = 100, n2 = 125, X= 615, x2 = 600, 6, = 40,02 = 24 O A. 0.0005 OB. 0.5105 OC. 0.1015 OD. 0.0505 The following data represent the yields for a five-year CD for ten banks in city A and eight banks in city B. At the 0.05 level...
Two researchers conducted a study in which two groups of students were asked to answer 42 trivia questions from a board game. The students in group 1 were asked to spend 5 minutes thinking about what it would mean to be a professor, while the students in group 2 were asked to think about soccer hooligans. These pretest thoughts are a form of priming. The 200 students in group 1 had a mean score of 26.2 with a standard deviation...