Question

A statistics instructor who teaches a lecture section of 160 students wants to determine whether students have more difficulty with one-tailed hypothesis tests or with two-tailed hypothesis tests. On the next exam, 80 of the students, chosen at random, get a version of the exam with a 10-point question that requires a one-tailed test. The other 80 students get a question that is identical except that it requires a two-tailed test. The one-tailed students average 7.81 points, and their standard deviation is 1.06 points. The two-tailed students average 7.64 points, and their standard deviation is 1.33 points.

Answer 1

There is no evidence that there is no significant difference between the sample means

Explanation:

given that a statistics instructor who teaches a lecture section of 160 students wants to determine whether students have more difficulty with one-tailed hypothesis tests or with two-tailed hypothesis tests. On the next exam, 80 of the students, chosen at random, get a version of the exam with a 10-point question that requires a one-tailed test. The other 80 students get a question that is identical except that it requires a two-tailed test. The one-tailed students average 7.81 points, and their standard deviation is 1.06 points

The two-tailed students average 7.64 points, and their standard deviation is 1.33 points.

Group One tailed X Two tailed Y

Mean 7.8100 7.6400

SD 1.0600 1.3300

SEM 0.1185 0.1487

N 80 80

`H_0:\bar x=\bar y\\H_a: \bar x \\eq \bar y`

(Two tailed test)

The mean of One tailed X minus Two tailed Y equals 0.1700

t = 0.8940

df = 158

p value =0.3727

p is greater than alpha 0.05

There is no evidence that there is no significant difference between the sample means