Statistics — Quiz 4

Questions in this quiz (5)

1. If all the elements of a set are multiplied by a constant, the average (arithmetic mean) remains unchanged, which of the following statements must be true?I. Average (arithmetic mean) = 0II. Sum of the elements of the set equals 0III. The set contains at least one positive and one negative number

   • I
   • II
   • III
   • I, II

2. If the median of X consecutive integers is 50.5, which is the smallest integer among the following?

   • $$50 - X$$
   • $$51 - X/2$$
   • $$50 - X/2$$
   • $$49 - X$$

3. The number of complaints received in eight of the nine customer service days are: $$5, 7, 9, 6, 4, 4, 8, 10$$, respectively. If the median number of complaints per day over all nine days is equal to the mean (arithmetic average) number of complaints per day over all nine days, then what is the number of complaints on the ninth day?

   • 1
   • 2
   • 3
   • 4

4. The median and mode of a distribution are 20 and 18, and then the mean is:

   • 60
   • 21
   • 42
   • 18

5. In a distribution of exam scores, 70% of the scores fall within 1 standard deviation from the mean, 88% of the scores fall within 2 standard deviations from the mean, and 96% of the scores fall within 3 standard deviations from the mean. What percentage of the scores fall between 2 and 3 standard deviations from the mean?

   • $$9%$$
   • $$6%$$
   • $$7%$$
   • $$8%$$