We have been given that the number of days that homes stay on the market before they sell in Houston is bell-shaped with a mean equal to 56 days. Further, 95 percent of all homes are on the market between 40 and 72 days.

As per empirical rule 95% of the data on bell curve lies between 2 standard deviations of mean.

So we can set an equation as:

$72-56=2\sigma$ or

$40-56=-2\sigma$

$16=2\sigma$

$\frac{16}{2}=\frac{2\sigma}{2}$

$8=\sigma$

$40-56=-2\sigma$

$-16=-2\sigma$

$\frac{-16}{-2}=\frac{-2\sigma}{-2}$

$8=\sigma$

Therefore, the standard deviation for our given data is 8 and option D is the correct choice.

6 0

2 years ago

Jolly measured the cake. Then she calculated that it has a circumference of 15cm. what is the cake's diameter? Use 3.14 for pi.

Hatshy [7]

Answer:

4.76cm

Step-by-step explanation:

Given data

circumference= 15cm

The expression for circumference is

C= 2πr

substitute and solve for r

15= 2*3.14*r

r= 15/ 2*3.14

r=15/ 6.28

r= 2.38 cm

Hence the diameter is

D= 2r

D= 2*2.38

D=4.76cm

6 0

2 years ago