A psychological researcher did a study with a sample of 84 boys and found that the meam length of time that they remained engage
d with a science exhibit at a museum was 107 second. assuming that from past studies it was known that the population standard deviation was 11.7 a) the best estimate for the population mean u is__
b) find the 99% confidence interval of mean length of time for a recent population
Sample size= n= 84 sample mean= x = 107 s population standard deviation =σ= 11.7
As, population standard deviation is given so we use the estimate: x(+/-) z(α/2)(σ/√n)
At 99% Confidence interval means significance level is α=1-0.99= 0.01 So, α/2=0.005 Now, z at α/2=0.005 z= 2.576 Now, by putting values 107(+/-)((2.576)(11.7/√84)) ( 107-((2.576)(11.7/√84)), 107+((2.576)(11.7/√84)) ) (103.7, 110.288)
