Question

QUESTION 17 Your instructor (Katie) believes that the average time of taking this exam is equal to 140 minutes. A sample of 4 students was taken and the following exam times were obtained. Assume the distribution of the population is normally distributed Sample: 150, 150, 180, 170 (Sample Std. Dev = 15) At a 0.1 level of significance, it can be concluded that the mean of the population is: a significantly less than 140 Ob not significantly different than 140 significantly greater than 140 Od significantly different than 140 3 QUESTION 18 For each shipment of parts a manufacturer wants to accept only those shipments with at most 10% defective parts. A large shipment has just arrived. A quality control manager randomly selects Sd of the parts from the shipment and finds that 6 parts are defective. State the null and alternative hypotheses Da HH30.1 and H3> 0.1 Hou0.1 and H<0.1 Hips 0.1 and H:p> 0.1 Hp2 0.1 und H,P<0.1 Click and submit on and click Save All Antowall MacBook BO

Answer 1

17. We are testing,

H0: u= 140 vs H1: u $\neq$ 140

From the sample given, sample mean= 162.5

Test statistic: (sample mean-140)/(sample SD/√n) = (162.5-140)/(15/√4) = 3

P-value of this two sided t3 test is:

2*P(t3>3) = 0.0577

Since the p-value of this test < significance level of 0.10, we have sufficient evidence to reject H0 and conclude that u is different from 140

So option d is correct.

18. Here, we are testing, (proportion of defects is less than 10%)

H0: p>=0.10 vs H1: p<0.10

So option d is correct.