Question

X ~ N(60, 12). Suppose that you form random samples of 25 from this distribution. Let X be the random variable of averages. Let ΣX be the random variable of sums.

Find the probability. (Round your answer to four decimal places.)

P(28 < X < 56)

Please if at all possible, list the steps on how to solve this using a TI84 calculator!

Answer 1

Let X be the random variable of averages.

X ~ N(60, 12). Suppose that you form random samples of 25 from this distribution.

Mean = = 60

Standard deviation = = 12

We have to find P(28 < X < 56).

By using the TI-84 calculator we have to find above probability.

Click 2ND------> VARS ------> normalcdf( -------->

lower: 28

upper: 56

: 60

: 12

Paste

We get probability 0.3656

P(28 < X < 56) = 0.3656