Question

2. A critic says to the investigator: “You should not assume that you know s for your population of 5^th graders. The standard deviation for them could be different from s for the general population.” The investigator still wants to do a null hypothesis significance test using the same data from four children, with Ho: mu = 100, but without assuming that s is known.

She decides to use the known m and s, adopts an a of .05, and uses a non-directional (i.e., 2-sided) alternative hypothesis.

IQ scores: 112, 110, 123, 115

Perform the null hypothesis significance test that is appropriate for this situation. Show your work; you may use a hand calculator and/or R to do your calculations, but do not use a statistical app or software that does all of the work for you. Briefly summarize your results and briefly state what they mean.

Answer 1

	IQ Score ( X )
	112	9
	110	25
	123	64
	115	0
Total	460	98

Mean

Standard deviation

To Test :-

H0 :-  

H1 :-  

Test Statistic :-


t = 37.4417

Test Criteria :-
Reject null hypothesis if

= 37.4417 > 3.182
Result :- Reject null hypothesis

Conclusion :- Accept Alternative Hypothesis

There is insufficient evidence to support the claim that average IQ score is 100 at 5% level of significance.