I'm not sure about my answers for b), c) & d). Am i right?

Question

anonymous · Answer

attachment

anonymous · Answer

@amistre64

amistre64 · Answer

the sampling distribution of the sample means are normally distributed,  that is the basis of the central limit thrm

the sample mean is an estimate of the population mean

and the sample standard deviation is a division by sqrt(n) of the population "sd"

the rest of it is of course using those as the parameters to find the probabilities

amistre64 · Answer

z > (90.9 - 87)/3;  1.3
z <= (80.1 - 87)/3; -2.3

(85.2 - 87)/3 < z < (92.25 - 87)/3
        -.06                       1.75

a normalCDF function would take care of those, or table it as needed

amistre64 · Answer

0.0968
0.0107

   9599
- 4761
------
0.4838