Statistics question regarding mean and variance


#1

I didn’t want to post this on wattpad but yahoo answers is apparently down.

So theres a homework question. I will change the numbers so I can figure out the real one by myself and you know not get in trouble for just getting the answers online

for example It gives me mean of 40, variance of 8, approximately 60% of scores fall between 32 and 48. It wants to know if this is true or false

I tried to look up similar problems, but only got the answers instead of steps on how to perform the solution

please show me some steps to figure these types of questions out


#2

Try simbolab.


#3

I will look into it thank you!


#4

oh I see. that would only be if I knew an equation to solve it in the first place


#5

Your 60% confidence interval would be from 32 to 48 -> this is what you want to validate

A confidence interval is mean ± Z score * standard deviation.
mean = 40
standard deviation = square root of the variance = 8^(1/2) = 2.8284
Z value for 60% = find it in a table for Z value EDIT: approx 1.28 for 80%

And calculate your CI and check if it’s 32-48
EDIT: it’s not, it’s 36.38 to 43.62 for a 80% CI.

Feel free to ask questions :hugs:


#6

Oops this Z score is for 80% CI. So 36.38 to 43.62 is your 80% CI.


#7

darn turned it in an hour and a half ago. doesn’t look like I would’ve gotten it right.
But now I understand how to do it thank you!


#8

omg i hate stats T-T