Average of daily rainfalls for weekdays and weekends
1. A sample of n = 9 has a mean of M = 10. One person with a score of X = 2 is removed from sample. What is the value of the new sample mean?
Hint: From the knowledge of n and M get the sum of the scores. Then subtract 2 from this sum and divide by the new n =8.
2. Does it ever seem to you that the weather is nice during the work week, but lousy on the weekend? Cerveny and Balling (1998) have confirmed that this is not your imagination; pollution accumulating during the work week most probable spoils weekend weather for people on the Atlantic coast. Consider the following hypothetical data showing the daily amount of rainfall for 10 wks throughout the summer.
Rainfall on Weekdays 1.2, 0.6, 0.0, 1.6, 0.8, 2.1, 0.2, 0 .9, 1.1, 1.4
Rainfall on Weekends 1.5, 2.0, 1.8, 1.5, 2.2 2.4, 0.8, 1.6, 1.2, 1.7
a. work out the average daily rainfall during the week and for the weekends. Hint: Obtain the average of the weekdays' rainfalls and the average of the weekend's rainfalls.
b. Based on the two means, does there appear to be a pattern in the data? Based on part (a) make your conclusion.