In a study of birth order and intelligence, IQ tests were given to 18 and 19 yea
ID: 3154783 • Letter: I
Question
In a study of birth order and intelligence, IQ tests were given to 18 and 19 year old men to estimate the similarity, if any, between mean IQ’s of firstborn sons and second born sons. Firstborn: n = 20, mean = 111.1, standard deviation = 10.6 Secondborn: n=20, mean = 112.6, standard deviation = 7.14 Using a 0.05 significance level, test the claim that the average IQ for a FIRSTBORN son is the same as the average IQ for the SECONDBORN son. • Write the claim using symbols (< or or > or or = or ): 111.1=112.6 • Write the claim again using the opposite symbol: 111.1112.6 • Label each statement. o (null hypothesis): o (alternative hypothesis): • Write the Critical value (the Table value) here: • Now use your calculator or the formula to tell me the calculated value (known as the “test statistic”): • REJECT : YES or NO • What is your conclusion?
Explanation / Answer
Ho : miu1 = miu 2 H1 : miu1 miu 2
t = ( 112.6 - 111.1) / srqt ( 10.6^2 +7.14^2 / 20 )
t = 0.52
critical value is 1.684
since t value < critical value we fail to reject Ho
there is no difference between the average IQ for the first and second born