In: Statistics and Probability
(10) The average tuition and room and board cost at a small private liberal arts college is reported to be $20,000 per term. A study of 400 small liberal arts colleges find that the average cost per term is $20,100. The population standard deviation is $1,500. If α = 0.05, what is the critical Z value for the test: Ho: µ= 20,000?
Solution :
Given that,
Population mean = = 20000
Sample mean = = 20100
Population standard deviation = = 1500
Sample size = n = 400
Level of significance = = 0.05
This is a two tailed test.
The null and alternative hypothesis is,
Ho: 20000
Ha: 20000
The test statistics,
Z =( - )/ (/n)
= ( 20100 - 20000 ) / ( 1500 / 400)
= 1.133
Critical value of the significance level is α = 0.05, and the critical value for a two-tailed test is
= 1.96
The critical value is 1.96
Since it is observed that | z |= 1.133 = 1.96, it is then concluded that the null hypothesis is fail to reject.