Consider the accompanying data on flexural strength MPa for

Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type.

Given that the accompanying data on flexural strength for concrete beams of certain type.

The point estimate of the mean value of strength for the conceptual population of all beams manufactured in this fashion is,Xbar that is sample mean.

sample mean (Xbar) = sum of observations / total number of observations.

There are 27 observations.

sum of observations = 218.9

sample mean (Xbar) = 218.9 / 27 = 8.107 * MPa

This is the point estimate of the population mean.

Calculate a point estimate of the strength value that separates the weakest 50% of all such beams from the strongest 50%.

Hedian we use sample median is the point estimate of the strength value that separates the weakest 50% of all such beams from the strongest 50%.

Median is the that value which divides data into two equal parts.

Sample median = Middle observation from the arranged data.

Here there are 27 observations that means

Median = [ (27 + 1) / 2 ]^th observation in arranged data.

Median = [ 28 / 2 ]^th observation

Median = 14^th observation in the arranged data.

Median = 7.7

The point estimate of the population variance is sample variance.

Sample variance we can calculate by using EXCEL command is

var(data)

This will gives us sample variance is 2.9353