Question

Time-Series Graphs. In Exercises 9 and 10, construct the time-series graph.

Gender Pay Gap Listed below are women’s median earnings as a percentage of men’s median earnings for recent years beginning with 1990. Is there a trend? How does it appear to affect women?

71.6 69.9 70.8 71.5 72.0 71.4 73.8 74.2 73.2 72.3 73.7 76.3 76.6 75.5 76.6 77.0 76.9 77.8 77.1 77.0 77.4 77.0

Short answer

The following time-series graph is constructed for the women’s earnings as a percentage of men’s earnings:

It can be observed that the women’s earnings as a percentage of men’s earnings appear to be gradually increasing over the years. Therefore, there is an upward trend.

This implies that an upward trend would be beneficial for women as it will help their earnings be equal to that of men.

Step-by-step solution

Given information

Data is provided on women’s median earnings as a percentage of men’s median earnings starting from the year 1990.

71.6 69.9 70.8 71.5 72.0 71.4 73.8 74.2 73.2 72.3 73.7 76.3 76.6 75.5 76.6 77.0 76.9 77.8 77.1 77.0 77.4 77.0

Describe a time-series plot

A time series plot is a graph that consists of observations plotted over a certain duration of time, say years.

Graphically, the years or months are marked on the horizontal axis, and the vertical axis represents the observations. The observations are plotted as points on the graph, and then all are joined to form a trend line.

Sketch the time series plot

The following table shows the median of women’s earnings from 1990:

Year	1990	1991	1992	1993	1994	1995
Earnings	71.6	69.9	70.8	71.5	72.0	71.4
Year	1996	1997	1998	1999	2000	2001
Earnings	73.8	74.2	73.2	72.3	73.7	76.3
Year	2002	2003	2004	2005	2006	2007
Earnings	76.6	75.5	76.6	77.0	76.9	77.8
Year	2008	2009	2010	2011
Earnings	77.1	77.0	77.4	77.0

Follow the below steps to sketch a time series plot:

• Draw a vertical axis starting from 69 with a one-unit increment.
• Plot years on the horizontal axis, starting from 1990 with a two-year increment.
• Mark the points on the graphs corresponding to the given year.
• Join the points with a line segment.
• Label the horizontal axis as “Year” and the vertical axis as “Percentage of Women’s Earnings.”

The following time-series graph is constructed:

Describe the trend

The trend is an approximate increase or decrease throughout the period. By observing the plot, it can be seen that the women’s earnings have gradually increased from 1990 to 2011. There is an upward trend.

Explain the effect on women

The median earning in terms of percentage with respect to men’s median earnings has increased. It implies that the gender gap in earning has lowered.

Thus, there is a positive effect that will help women achieve earnings equal to those of men.