The probability that an individual is left-handed is 0.19. In a class of 90 students, what is the mean and standard deviation of the number of left-handed students? Round to the nearest hundredth when necessary.

Mean = 17.1

SD = 3.72

Step-by-step explanation:

FROM the question;

n = 0.19 and the probability of success is 0.19

Mean = np = 0.19 * 90 = 17.1

The standard deviation is as follows;

√np(1-p)

SD = √(17.1)(0.81)

SD = √13.851

SD = 3.72

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have