Question

How can I find the required sample size on a Ti83?

Answer 1

have a look at this page

https://www.ltcconline.net/greenl/courses/201/estimation/ciprop.htm

let me know if it helps or not. Also, post the full problem if you can

Answer 2

An IQ test is designed so that the mean is 100 and the SD is 10 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is within 2 IQ points of the true mean. Assume that the SD=10 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.

Answer 3

thanks

Answer 4

did that link help at all?

Answer 5

you'll use a formula given on that page

Answer 6

I'll try it out

Answer 7

Im not sure which solution to use?

Answer 8

How can I put it into my ti83?

Answer 9

you'll use the formula

\[\Large n = \left(\frac{z_c*\sigma}{E}\right)^2\]

as shown on that page

Answer 10

\(\Large z_c\) is the critical z value based on the confidence level

You'll find using a table or calculator that \(\Large z_c \approx 1.645\) at the 90% confidence level

Answer 11

You are given

\[\Large \sigma = 10\]
\[\Large E = 2\]

Answer 12

I got 16.45

Answer 13

\[\Large n = \left(\frac{z_c*\sigma}{E}\right)^2\]
\[\Large n = \left(\frac{1.645*10}{2}\right)^2\]
\[\Large n = ???\]

Answer 14

Yep, that is what im getting... Idk what I am doing wrong?

Answer 15

you only computed 1.645*10 to get 16.45

Answer 16

you forgot to divide that result by 2

then square that result

Answer 17

9.069

Answer 18

incorrect

Answer 19

\[\Large n = \left(\frac{z_c*\sigma}{E}\right)^2\]
\[\Large n = \left(\frac{1.645*10}{2}\right)^2\]
\[\Large n = \left(\frac{16.45}{2}\right)^2\]
\[\Large n = \left(8.225\right)^2\]
\[\Large n = ???\]

Answer 20

67.65

Answer 21

then you round that up to the nearest whole number

Answer 22

68

Answer 23

so n = 68 is the required sample size

Answer 24

Thank you

Answer 25

yw