Assume the height of females aged 20-29 years ols is normally distributed with a mean of 64.1 and a SD of 2.8 inches. Suppose a random sample of 4 girls is selected. What is the probability that all four will be 66 inches or taller?

Question

Assume the height of females aged 20-29 years ols is normally distributed with a mean of 64.1 and a SD of 2.8 inches.  Suppose a random sample of 4 girls is selected. What is the probability that all four will be 66 inches or taller?

amistre64 · Answer

what is your test statistic?

amistre64 · Answer

or better yet, do you have a ti83 by chance?

anonymous · Answer

TI 89!

amistre64 · Answer

eww 89 eh,  im not sure how much they changed it from the 83s

anonymous · Answer

Im not sure.  I can calculate the test statistic though.

amistre64 · Answer

is there a 2nd and a VARS bttons?

anonymous · Answer

VARS-LINK

amistre64 · Answer

any thing that contains a normalCDF function?

amistre64 · Answer

the question is reading odd to me

its either saying, find the probability of 66 and above and ^4 it

or it is saying we modify the test statistic by sqrt(4) .... i originally thought the second, but the first is making more sense to me

anonymous · Answer

This is the 3rd part of the question. In part a I found the probability of the whole population between 62 and 68 in.  and in part b I found the probability that a random sample person will be 66 in or taller.

amistre64 · Answer

(66-64.1)/2.8 ... oh good, then you already have the 66 or taller

amistre64 · Answer

24.87% of picking a random person and getting 66 ir taller

anonymous · Answer

yes I do.  Do I raise that answer to 4?

amistre64 · Answer

if we pick 4 people then (true and true and true and true) is yeah, prob 66up raised to teh 4th

anonymous · Answer

turns out to be .3%

amistre64 · Answer

.38% iswhat i see

anonymous · Answer

yes sorry, i got that as well

amistre64 · Answer

cool

anonymous · Answer

Thank you!    and could I ask one more part?

amistre64 · Answer

sure

anonymous · Answer

It reads "What is the distribution of the sample mean? Provide all characteristics"

amistre64 · Answer

did you take a sample beforehand?  this might be easier to determine if you caould take a screenshot :/

anonymous · Answer

ok I will get a picture of it!

amistre64 · Answer

by the central limit thrm, the mean of the sample means is normally distributed; but to ask how a single sample mean is distributed just reads bad

anonymous · Answer

attachment

anonymous · Answer

I figured that the answer was that it was normally distributed but it must be looking for more

amistre64 · Answer

pffftttt, yeah i got no idea what that is asking for :/ this might be useful tho: http://onlinestatbook.com/2/sampling_distributions/samp_dist_mean.html

anonymous · Answer

Thanks! i'll take a look!  I appreciate your help!

amistre64 · Answer

thats all i got for it :)  good luck