Two independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal. The sample sizes are n 1 = 25 and n 2 = 30. The correct distribution to use is the t distribution with _____ degrees of freedom.
Two independent simple random samples are taken to test the difference between the means of two...
A researcher collects two independent random samples of sizes n = 22 and n2 = 27, and computes the means, x, and x2 and the standard deviations, s, and s2, of each sample. She plans to use a t-test to determine if there is a difference between the two population means, Hi and 2. She does not know the population standard deviations, nor does she have any reason to believe that they are equal. Using the most conservative approach, calculate...
16. In order to compare the means of two populations, independent random samples are selected from each population, with the following results. n 11, You are asked to use the pooled t-test to test 0.95, 0.049, 2 16, 20.61, s20.028 Find the observed value of the test statistic (a) 60.8873 with 25 degrees of freedom (b) t 85.0113 with 25 degrees of freedom. (c) 4.5499 with 25 degrees of freedom. (c) (d) None of the above.
Two random samples are selected from two independent populations. A summary of the samples sizes, sample means, and sample standard deviations is given below: n1= 37 n2=44 x-bar1= 58.6 x-bar2= 73.8 s1=5.4 s2=10.6 Find a 97% confidence interval for the difference μ1−μ2μ1−μ2 of the means, assuming equal population variances.
Two random samples are selected from two independent populations. A summary of the samples sizes, sample means, and sample standard deviations is given below: n1=51, n2=46, x¯1=57.8, x¯2=75.3, s1=5.2 s2=11 Find a 94.5% confidence interval for the difference μ1−μ2μ1−μ2 of the means, assuming equal population variances. Confidence Interval =
Two samples each of size 20 are taken from independent populations assumed to be normally distributed with equal variances. The first sample has a mean of 43.5 and a standard deviation of 4.1 while the second sample has a mean of 40.1 and a standard deviation of 3.2. A researcher would like to test if there is a difference between the population means at the 0.05 significance level. What can the researcher conclude? There is not sufficient evidence to reject...
Consider the following results for independent random samples taken from two populations. Sample 1 Sample 2 n1= 20 n2 = 40 x1= 22.1 x2= 20.6 s1= 2.9 s2 = 4.3 a. What is the point estimate of the difference between the two population means (to 1 decimal)? b. What is the degrees of freedom for the t distribution (round down)? c. At 95% confidence, what is the margin of error (to 1 decimal)? d. What is the 95% confidence interval...
For the independent-measures t test, which of the following describes the estimated standard error of M1 - M2 (whose symbol is )? O The variance across all the data values when both samples are pooled together O A weighted average of the two sample variances (weighted by the sample sizes) O The difference between the standard deviations of the two samples O An estimate of the standard distance between the difference in sample means (M, - M2) and the difference...
Assume that two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Which distribution is used to test the claim that mothers spend more time (in minutes) driving their kids to activities than fathers do? A. F B. t C. Chi-square D. Normal
Consider the following results for independent random samples taken from two populations. Sample 1 Sample 2 n 1 20 n 2 40 x2 20.4 1= 22.5 S 2 4.6 s1 2.1 a. What is the point estimate of the difference between the two population means (to 1 decimal)? b. What is the degrees of freedom for the t distribution (round down your answer nearest whole number)? c. At 95% confidence, what the margin of error (to 1 decimal)? d. What...
Exercise 10.9(Algorithmic)) Consider the following results for independent random samples taken from two populations Sample 1 Sample 2 n1 10 n2 30 x1- 22.8 x2 20.9 $1-2.9 s2 4.8 a. What is the point estimate of the difference between the two population means (to 1 decimal)? b. What is the degrees of freedom for the t distribution (round down)? C. At 95% confidence, what is the margin of error (to 1 decimal)? d. what is the 95% confidence interval for...