Question

2 1 pts Question 6 6) How many women must be randomly selected to estimate the mean weight of women in one age group. We want 90% confidence that the sample mean is within 3.4 lb of the population mean, and the population standard deviation is known to be 25 lb. O 146 O 148 208 O 147 Question 7 1 pts ZIA group of 39 randomly selected students have a meanscore of 19.5 with a JUL 3 31 19 DOC

Answer 1

Solution:

Given ,

$\sigma$ = 25 ..Population SD

E = 3.4 Margin of error

c = 90% = 0.90 ...confidence level

$\therefore$$\alpha$ = 1- c = 1- 0.90 = 0.10

$\therefore$  $\alpha$/2 = 0.05

Using Z table ,

$\therefore$ = 1.645

2012

Now, sample size (n) is given by,

"a/2 * o n n = E

=  {(1.645* 25 )/ 3.4 }²

= 146.30

= 147 ..(round to the next whole number)

Answer is

147