Answer:
21.16
Step-by-step explanation:
Starting from the theory we have the following equation:

Using the data supplied in the exercise, we have subtracting the mean and dividing by the standard deviation:

solving for "c", knowing that fi is a tabulating value:

therefore the value of c is equal to 21.16
<h3>a)

</h3><h3>■Dividing a positive and a negative equals a negative: (+)÷(-)=(-)</h3>
<h2>

</h2><h3>■To divide by a fraction, multiply by the reciprocal of that fraction</h3>
<h2>

</h2><h3>■Multiply the fractions</h3>
<h2>

</h2>
<h3>Hence, Quotient =

</h3>
<h3>b)

</h3><h3>■Convert the decimals into a fractions</h3>
<h2>

</h2><h3>■Dividing a positive and a negative equals a negative: (+)÷(-)=(-)</h3>
<h2>

</h2><h3>■To divide by a fraction, multiply by the reciprocal of that fraction</h3>
<h2>

</h2><h3>■Multiply the fractions</h3>
<h2>

</h2><h3>Hence, Quotient is

</h3>
<h3>c)

</h3><h3>■To divide by a fraction, multiply by the reciprocal of that fraction</h3>
<h2>

</h2><h3>■Multiply the fractions</h3>
<h2>

</h2><h3>Hence, The Quotient is

</h3>