User`s guide

Statistical Calculations124
Estimate what the level of sales would be if the business purchased 7 or 8 minutes of
advertising.
How many minutes of advertising should Ali’s buy to attain sales of 3,000?
Weighted Mean
The following procedure calculates the weighted mean of data points x
1
, x
2
, …, x
n
occurring
with weights y
1
, y
2
, …, y
n
.
1. U s e
Æ and ¡ to enter x,y pairs. The y-values are the weights of the x-values.
2. Press
\T.
Example 5
A survey of 266 one-bedroom rental apartments reveals that 54 of them rent for 500 per
month, 32 for 505, 88 for 510, and 92 for 516. What is the average monthly rent?
\Z\«
0.90 Calculates correlation
coefficient.
Table 12-11 Estimating the level of sales
Keys Display Description
j\W
3,357.38 Estimates sales if 7 minutes of
advertising were purchased.
g\W
3,783.25 Estimates sales if 8 minutes were
purchased.
Table 12-12 Estimating the minutes of advertising for 3,000 sales
Keys Display Description
D:::\Z
6.16 Estimates minutes of advertising
required for 3,000 in sales.
Table 12-10 Example for forecasting
Keys Display Description