Question

Past experience indicates that the time required for high school seniors to complete a standardized test is a normal random variable with a standard deviation of minutes. Test the hypothesis that against the alternative that if a random sample of the test times of high school seniors has a standard deviation . Use a level of significance.

Answer 1

Complete question :

Past experience indicates that the time required for high school seniors to complete a standardized test is a normal random variable with a mean of 35 minutes. If a random sample of 20 high school seniors took an average of 33.1 minutes to complete this test with a standard deviation of 4.3 minutes, test the hypothesis, at the 0.05 level of significance.

Answer:

We conclude they there is significant evidence to support the claim That time required for high school seniors to complete test is less than 35 minutes.

Step-by-step explanation:

H0 : μ = 35

H1 : μ < 35

Sample size, n = 20

Standard deviation, s = 4.3

xbar = 33.1

Test statistic :

T = (xbar - μ) ÷ (s /√n)

T = (33.1 - 35) ÷ (4.3 /√20)

T = - 1.9 ÷ 0.9615092

T = - 1.976

The Pvalue can be obtained from the test statistic using a Pvalue calculator :

Pvalue at 0.05 ; df = 19 is 0.0314

Since, Pvalue < α ; We reject the Null and conclude that time required for high school candidate to complete test is less than 35 minutes