Question

Out of 100 students sampled, 70 of them said that they hoped to get married someday. With 99.7% confidence, what is the approximate percentage of the students in the population who hope to get married someday?

A. 60.8% to 79.2%
B. 65.4% to 74.6%
C. 56.3% to 83.7%
D. 51.7% to 88.3%

Answer 1

I have added them all up and divided by two and they all give me 70. I know that 99.7% confidence equals +- 3 I am just not sure what to do from their?

Answer 2

@jim_thompson5910

Answer 3

I know that 70 of 100 is 70% (0.70)

Answer 4

use the formulas

L = p - z*sqrt(p*q/n)
U = p + z*sqrt(p*q/n)

where...

p = sample proportion
z = critical value
q = 1-p
n = sample size

Answer 5

I don't know if I plugged the numbers in right .7-sqrt(.7)(1-.7)/100 and got 0.654 with I think would be 65.4%

Answer 6

you forgot about z

Answer 7

what number is z is that 3

Answer 8

I got C. 56.3% to 83.7%

Answer 9

correct