Question

In: Statistics and Probability

Allow X to represent the duration of an 8-month-old baby's smile. Where X is normally distributed...

Allow X to represent the duration of an 8-month-old baby's smile. Where X is normally distributed with a mean of 9.1 seconds and a standard deviation of 2.2 seconds.

a) What is the probability that a randomly chosen baby smiles between 6 and 12 seconds?

Expert Solution

Given Population Mean =

Populattion Standard Deviation =

Between 6 & 12

P(6 < X < 12) = ?

We know that the Standard Normal Variate is Z;

Also

We have to find the probability of the Shaded Aread.

NOTE; Probability value of Z has been extracted from the Standard Normal tabulated value; which posted below.

For P(Z=-1.42) Search the value which is intersected at 1.4 and 0.01; we will get the value 0.4207. Similarly search the other probability which is intersected at 1.3 and 0.02; we get 0.4066

orchestra answered 2 years ago

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