9.1.25
a)p=0.179
b)the sample size can be assumed to be a simple random sample the value of np(1p)is 335.65 which is greater then or equal to 10 and the sample size can be assumed to be less then or equal to 5% of the population size.
d)interpreted intervals is between .1676 and .1940
9.2.19
a)lower bound 16.854 upper bound 19.946
b)increasing sample sizesmdecreases the margin of error. lower bound 17.121 upper bound 19.679
c)decreased levels of confidence increases margin of error, lower bound 16.235 upper bound 20.475
d) if n=15 then the sample data needs to come from population thats normally distrubuted with no outliers
9.3.15
a)data is normal distrubution based on the normal probability plot as points lie closely to red line which is used to reference normality.
b)sample standard deviation which is found using summary stats is equal to 0.349
c) 90% confidence intervals equal 0.261 and 0.541 which is found by using square root on initial lower and upper bounds.
d)the lower confidence interval is greater then 0.20 so the confidence interval is not validate the disired criteria.
Summary statistics:

One sample variance confidence interval:σ^{2} : Variance of variable 90% confidence interval results:

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