Question

The amount of rain for three months (June, July, and August) was recorded for each of three cities. Using the data in the following table, create a SAS data set (RAIN) containing the variables CITY, RAIN_JUNE, RAIN_JULY, AND RAIN_AUGUST. Create four additional variables in this data set: AVERAGE, PERCENT_JUNE, PERCENT_JULY, and PERCENT_AUGUST. AVERAGE is the average of the rain for the three months. Each of the PERCENT variables is computed as rainfall for the month as a percent of the AVERAGE. For example, PERCENT_JUNE would be 100 * 23/26. Provide a listing of the data set in alphabetical order of CITY, with CITY as the ID variable. Then compute the mean, standard deviation, and the 95% confidence interval (CI) for the three RAIN variables (with all statistics printed with two decimal places). Here are the data:

CITY RAIN_JUNE RAIN_JULY RAIN_AUGUST

Trenton 23 25 30

Newark 18 27   22

Albany 22 21 27

Answer 1

City	Rain_June	Rain_July	Rain_August	Average	Percent_June	Percent_July	Percent_August
Albany	22	21	27	23.33	94.29	90.00	115.71
Newark	18	27	22	22.33	80.60	120.90	98.51
Trenton	23	25	30	26	88.46	96.15	115.38

mean, standard deviation, and the 95% confidence interval (CI) for the three RAIN variables Percent_June,Percent_July and Percent_August.

Mean =

std dev s =

95% CI =

n = 3, alpha = 0.05, t_0.025,2 = 4.303

Sample	N	Mean	StDev	SE Mean	95% CI for μ
Percent_June	3	87.78	6.87	3.97	(70.72, 104.85)
Percent_July	3	102.35	16.35	9.44	(61.73, 142.97)
Percent_August	3	109.87	9.84	5.68	(85.42, 134.31)

μ: mean of Percent_June, Percent_July, Percent_August