Of course, it\'s totally unrealistic to think that the university knows the popu
ID: 3249150 • Letter: O
Question
Of course, it's totally unrealistic to think that the university knows the population standard deviation of the number of alcoholic drinks per week for male students. Answer the following questions using just what you know from your sample (x bar= 5.9, s =1.44, n =25) What is the probability of choosing a sample with the mean number of drinks between 5.0 and 5.6 per week? Not using the population information (which you wouldn't realistically know), calculate a 90% confidence interval for mean number of drinks of male students at UW Not using the population information (which you wouldn't realistically know), calculate a 95% confidence interval for mean number of drinks of male students at UW Is the 90% confidence interval for question 2b wider or smaller than the 95% confidence interval for question 2c? Why? Is the 90% confidence interval for question 2b wider or smaller than the 90% confidence interval for question ld? Why?Explanation / Answer
mean = 5.9 , s = 1.44, n = 25
a)
P(5 < x < 5.6)
P(x < 5)
z = ( x - mean) / ( s/sqrt(n))
= ( 5 - 5.9 ) / ( 1.44 /sqrt(25))
= -3.125
P(x < 5.6)
z = ( x - mean) / ( s/sqrt(n))
= ( 5.6 - 5.9 ) / ( 1.44 /sqrt(25))
= -1.042
P(5 < x < 5.6) = P( -3.125 < z < -1.042) = 0.4814
b)
z value at 90% CI = 1.645
CI = mean + /- z * ( s / sqrt(n))
= 5.9 +/- 1.645 * ( 1.44/sqrt(25))
= (5.426 ,6.374)
c)
z value at 95% CI = 1.96
CI = mean + /- z * ( s / sqrt(n))
= 5.9 +/- 1.96 * ( 1.44/sqrt(25))
= (5.335 ,6.464)
d)
Higher confidence levels have wider intervals than lower confidence levels (all other things being equal).
So, 90% confidence interval are smaller than 95% CI
e)
Higher confidence levels have wider intervals than lower confidence levels (all other things being equal).
So, 95% confidence interval are wider than 90% CI
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.