Question # 2. Your local pizza chain claims that the delivery time of their pizz
ID: 2960623 • Letter: Q
Question
Question # 2. Your local pizza chain claims that the delivery time of their pizzas is normally distributed with a mean of 30 minutes.Twenty of your friends in different locations order pizzas. The average delivery time is 42 minutes and the standard deviation is 10 minutes. Significance level (a=0.05)
Is there any difference of the pizzas delivery time between the sample average and company's claim?
Question 15
1.
What is the null hypothesis for this question?
Answer
H0: µH = 30
Ha: µH = 30
H0: µH =42
Ha: µH > 30
Ha: µH == 30
Question 16
1.
What is the alternative hypothesis for this question?
Answer
H0: µH = 30
Ha: µH = 30
H0: µH =42
Ha: µH == 30
Ha: µH > 30
Question 17
1.
What is the value of standard error of the mean? _____ (x.xx)
Answer
Question 18
1.
What is the calculated t value for this question? (x.xx)
Answer
Question 19
1.
What is the critical t value for this question? X.xx (find it from t table)
Answer
Question 20
1.
What is the decision making?
Answer
Reject H0
Accept H0
Question 21
1.
What is the conclusion for this question? Do you have reason to disbelieve the chain’s claim?
Answer
The sample mean is significantly longer than the population mean.
The sample mean is significantly shorter than the population mean.
The sample mean is significantly different from the population mean.
The sample mean is equal to the population mean.
no answer
Question 22
1.
What is the lower limit of the 95% confidence interval of the delivery time? ____ (x.xx, do not write unit)
Answer
Question 23
1.
What is the upper limit of the 95% confidence interval of the delivery time? ____ (x.xx)
Answer
Question 24
1.
Can you use one-sample t test for the following application?
You want to know if the average salary for males is the same as the average salary for females. You have available a sample of male salaries and female salaries.
Answer
no
yes
Question 25
1.
Can you use one-sample t test for the following application?
You want to know if the average difference in systolic blood pressure in a standing and reclining position is 0. You have values for differences for 54 people.
Answer
no
yes
Question 26
1.
Can you use one-sample t test for the following application? You want to know if the average ACT score for your school is 18.
Answer
yes
no
Question 27
1.
Can you use one-sample t test for the following application? You want to know if two schools have the same average ACT scores.
Answer
yes
no
Explanation / Answer
15.H0: µH = 30
16.Ha: µH == 30
17.standard error of the mean=s/n=10/sqrt(20)= 2.236
18.test statistic is t=(42-30)/2.236= 5.366
19. the critical t value= t(a=0.025, df=n-1=9)=2.26 (check student t table)
20. test statistic is t=(42-30)/2.236= 5.366 > 2.26, reject Ho.
21.The sample mean is significantly different from the population mean.
22.lower limit of the 95% confidence interval = xbar - {t(0.05, df=9)=1.83}*s/n
=42 - 1.83*2.236 = 37.90812
23.Upper limit of the 95% confidence interval = 42 + 1.83*2.236=46.09188
24.no
25.yes
26.yes
27.no