Your assignment is to prepare and submit a paper on statestic. Is Life Expectancy at Birth Differ By Gender? Jassim Alnajjar DSCI Section: 002 Case 2 Semester/Year: Fall -2009 Name: Dr. Marin Sabo

Abstract

Life expectancy at birth is the average number of years a newborn infant would live if the health and living conditions at birth remain same throughout its life. Worldwide life expectancy has risen on average by 4 months each year since 1970. This case study will analyze whether there is a difference in life expectancy at birth for male and female population.

Life Expectancy at Birth

Life expectancy at birth is the average number of years a newborn infant would live if the health and living conditions at birth remain same throughout its life. Since 1970, worldwide, on average there is increase of about 4 months in life expectancy at birth. Further, it has been observed that on average life expectancy at birth for female is greater as compared to male. This paper will analyze whether there is a difference in the life expectancy at birth for male and female population.

The data for life expectancy at birth was taken from US Census Bureau. The main benefit that data shows is that from period 1970 to 2005 female life expectancy at birth is greater as compared to male life expectancy at birth. In addition, the data is chosen so that it can be seen actually that living and health conditions are improving day by day and so life expectancy at birth is improving every year.&nbsp.

Figure 1 shows the comparison of US male and female life expectancy at birth for the period 1970 to 2005. It can be seen from figure 1 that for the whole period of 1970 to 2005, female life expectancy at birth was greater than male life expectancy at birth by nearly 7 years. Therefore, it appears that there is a difference in male and female life expectancy at birth. The average male and female life expectancy at birth for the period 1970 to 2005 was about 71.41 years (SD = 2.33), and 78.2 years (SD = 1.53), respectively.

The research question is “Is there a difference in life expectancy at birth for male and female populations?

The null and alternate hypotheses are

(Female and male life expectancy at birth are equal.)

(Female life expectancy at birth is different from male life expectancy at birth.)

The selected significance level, α is 0.05.

As the sample size (n1 + n1 &gt. 30) is large, the selected test is Independent Sample z-test.

At significance level of 0.05, the two-tail critical value of z is ±1.960. Therefore, the decision rule will be

Reject H0 if z &gt. 1.960 or z &lt. -1.960. Otherwise, do not reject H0.

Using MegaStat, the test statistic is

Z = 14.52

P-value &lt. 0.001 (two-tailed)

Since, the value of test statistic 14.52 falls in right-tail rejection region (greater than critical value of 1.96), thus decision is to reject H0. Therefore, there is a difference in life expectancy at birth for male and female populations.