Question

A concrete mix is designed to withstand 3000 pounds per square inch​ (psi) of pressure. The following data represent the strength of nine randomly selected casts​ (in psi). 3970​, 4100​, 3100​, 3200​, 2950​, 3830​, 4100​, 4050​, 3460 Compute the​ mean, median and mode strength of the concrete​ (in psi). Compute the mean strength of the concrete. Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice. A. The mean strength of the concrete is nothing psi of pressure. ​(Round to the nearest tenth as​ needed.) B. The mean does not exist.

Answer 1

Answer:

Mean = 3640

Mode = 4100

Median = 3830.

Step-by-step explanation:

We are given the following data in the question:

Strength of casts (in psi):

3970,4100,3100,3200,2950,3830,4100,4050,3460

Formula:

$Mean = \displaystyle\frac{\text{Sum of all observation}}{\text{Total number of observations}}$

$\displaystyle\frac{3970+4100+3100+ 3200+ 2950+ 3830+4100+ 4050+ 3460}{9} = \displaystyle\frac{32760} {9} = 3640$

Mode is the entry with most frequency. Thus, for the given sample mode = 4100.

Median

Since n = 9 is odd,

Formula:

$Median = \displaystyle\frac{n+1}{2}th~term$

Data in ascending order:

2950,3100,3200,3460,3830,3970,4050,4100,4100

Median = 5th term = 3830.