Question

. Use the graph below to investigate the correlation between the two variables. Please justify your answer. Correlation Study of Kt Kats and Course Load 0.45 m If the 95% confidence interval limits for the population mean are 70 and 80, which of the following could be the 90% confidence interval limits? Please justify your answer. A. 72 and 78 B. 65 and 75 C. 65 and 85 D. 72 and 85 n. A TV ad claims that a certain brand of tire has an average lifetime of more than 60,000 miles. Suppose you plan to test this claim by taking a sample of tires and put them to test. The correct set of hypotheses to set up is: "s60000 в.Ho: "-60.000 с.He: sa-60.000 and and and HA: μ>60,000 HA: ">60,000 o* : H-60,000and HA: 6000

Answer 1

l.

We have r = - 0.14

and P-value = P = 0.45

Let us take 5 % level of significance for the test

Null hypothesis : There is no significant correlation between the two variables.

Alternative hypothesis : There is significant correlation between the two variables.

Since, P-value = 0.45 > 0.05 ( Level of significance ) , we do not reject null hypothesis and conclude that there is no significant correlation between the two variables.

m.

Correct option : B. 65 and 75

Reason : As confidence level decreases, the width of the confidence interval also decreases. Since, we used 95% confidence level to get 70 and 80 as limits . If we decrease the level to 90% then interval will become shorter.

65 and 75 will be the limits as the interval becomes narrower.

n.

Correct option : A.

$H_o:\mu\leq 60000$

$H_1:\mu> 60000$