7.12.a 7.12.b 7.12.c

Statistics 7th Grade

Texas Essential Knowledge and Skills (TEKS): 7.12.a
compare two groups of numeric data using comparative dot plots or box plots by comparing their shapes, centers, and spreads;
Texas Essential Knowledge and Skills (TEKS): 7.12.b
use data from a random sample to make inferences about a population; and
Texas Essential Knowledge and Skills (TEKS): 7.12.c
compare two populations based on data in random samples from these populations, including informal comparative inferences about differences between the two populations.

A representative sample can be used to make predictions about a population.

In the sample, 33 out of 100 customers ordered water, which is

\frac{33}{100}

= 33% of the customers.
So, it can be predicted that 33% of the 1,000 customers would order water.

Measures of center and variability can be used to make
generalizations about the relationship between two sets of data.

First, find the mean of data set 1.

\begin{array}{rcl} \frac{18 + 15 + 20 + 17 + 15}{5} & = & \frac{85}{5} \\ = & 17 \end{array}

Next, find the mean of data set 2.

\begin{array}{rcl} \frac{25 + 24 + 22 + 16 + 23}{5} & = & \frac{110}{5} \\ = & 22 \end{array}

Statistics