All of these questions correspond to the first question. Thank you! According to
ID: 3257179 • Letter: A
Question
All of these questions correspond to the first question. Thank you!
According to the National Association of College Stores, average textbook cost is $670 a year. You think this is an understatement and want to prove that the average cost is greater than 670 a year. You survey a random sample of n 140 students. Your survey yields a sample mean of X 688 and standard deviation s 148. At a 5 percent level of significance, does the sample evidence lead you to conclude that the average cost is greater than $670 per year? Which of the following correctly expresses the null and alternative hypotheses for the test? a Ho: 670 H1: u S 670 b Ho: 670 H1: 670 c Ho: u 670 H1: 670 d Ho: Lu S 670 H1: u 670 Regardless of how you answered the previous question, which of the following statements is correct? a If the mean cost of text books is in fact greater than $670 and you conclude that it is at most $670, then you have committed a Type I error. b If the mean cost of text books is in fact greater than $670 and you conclude that it is at most $670, then you have committed a Type II error. c If the mean cost of text books is at most $670 and you conclude that it is greater than $670, then you have committed a Type II error. d If the mean cost of text books is less than $670 and you conclude that it is at least $670, then you have committed a Type II error.Explanation / Answer
The statistical software output for this problem is:
One sample T hypothesis test:
: Mean of population
H0 : < 670
HA : > 670
Hypothesis test results:
Hence,
Null and alternative hypotheses: Option D is correct.
Error: Option B is correct.
Test statistic = 1.44; Do not reject Ho; Option C is correct.
P - Value = 0.0749; Option D is correct.
Mean Sample Mean Std. Err. DF T-Stat P-value 688 12.508283 139 1.4390464 0.0749