Refer to the following frequency distribution for Questions 1, 2, 3, and 4.
The frequency distribution below shows the distribution for suspended solid concentration (in ppm) in river water of 50 different waters collected in September 2011.
Concentration (ppm) Frequency
20 - 29 1
30 - 39 8
40 - 49 8
50 - 59 6
60 - 69 16
70 - 79 7
80 - 89 2
90 - 99 2
Q1. What percentage of the rivers had suspended solid concentration less that 50?
Q2. Calculate the mean of this frequency distribution.
Q3. In what class interval must the median lie? Explain your answer. (You don't have to find the median)
Q4. Assume that the largest observation in this dataset is 98. Suppose this observation were incorrectly recorded as 988 instead of 98. Will the mean increase, decrease, or remain the same? Will the median increase, decrease or remain the same? Explain your answers.