The percent of female wage and salary workers who are paid hourly rates is given in the table for the years 1979 to 1992.
| Year | Percent of Workers Paid Hourly Rates |
| 1979 | 61.2 |
| 1980 | 60.7 |
| 1981 | 61.3 |
| 1982 | 61.3 |
| 1983 | 61.8 |
| 1984 | 61.7 |
| 1985 | 61.8 |
| 1986 | 62.0 |
| 1987 | 62.7 |
| 1990 | 62.8 |
| 1992 | 62.9 |
- Using year as the independent variable and percent of workers paid hourly rates as the dependent variable, draw a scatter plot of the data.
- Does it appear from inspection that there is a relationship between the variables? Why or why not?
- Does the y-intercept, a, have any meaning here?
- Calculate the least-squares line. Put the equation in the form ŷ = a + bx.
- Find the correlation coefficient. Is it significant?
- Find the estimated percentages for 1991 and 1988.
- Based on the data, is there a linear relationship between the year and the percentage of female wage and salary earners who are paid hourly rates?
- Are there any outliers in the data?
- What is the estimated percentage for the year 2050? Does the least-squares line give an accurate estimate for that year? Explain why or why not.
- What is the slope of the least-squares (best-fit) line? Interpret the slope.
OpenStax Statistics, 12.5 Outliers, exercise 22