Statistics Test...

Set P consists of 10 positive integers arranged in order of increasing magnitude. The difference between any two successive
terms of the set is 4. If the two largest terms of the set are removed, what is the decrease in the average(arithmetic mean) of
the set?

A is the average (arithmetic mean) of the first 7 multiples of 3 and B is the median of the first 3 multiples of positive integer n. If the
value of A² –B² is zero, what is the value of n?

Set P contains 3 distinct positive integers: A, B and C. Is the average (arithmetic mean) of set P divisible by 3?
(1) The sum of A ×10⁴ , B ×10² and C is divisible by 9
(2) The product of the range of Set P and the median of Set P is 18.

A set consists of n distinct integers arranged in the order of increasing magnitude. Is the median of the n integers equal to the
arithmetic mean of the n integers?
(1) The sum of any 3 successive integers of the set is divisible by 3
(2) The difference between any 2 successive integers of the set is 4

Set A consists of 15 positive integers. Is the mean of set A equal to the median of set A?
(1) The integers in set A, when arranged in the order of increasing magnitude, are not evenly spaced
(2) If an integer x, which is equal to the mean of set A, is added to the set, the median of the set does not change

A merchant sold 32 antique items for $28800. If his profit margin was 20%, then his average cost per antique item was

List A contains 16 distinct odd integers and 9 distinct even integers such that the average (arithmetic mean) of List A is 13.84. If each odd integer is doubled in magnitude, what is the new average (arithmetic mean) of List A?
(1) The average (arithmetic mean) of the even integers in List A is 10
(2) Before each odd integer is doubled in magnitude, the smallest odd integer in List A is 1 and the largest odd integer in List A is 31.

While debugging a piece of software, an engineer records the number of bugs he finds each day. If the number of bugs found by the engineer reduces by x with each passing day, what is the standard deviation of the number of bugs found by the engineer during the last 7 days?
(1) The difference between the maximum number of bugs and the minimum number of bugs found by the engineer during the last 7
days is 24.
(2) The average (arithmetic mean) number of bugs found by the engineer during the last 7 days is 24

A group of 4 boys and 5 girls take a test. What is the average (arithmetic mean) score of the group in the test?

1. The average score of the boys is 23 points while the average score of the girls is 20 points
2. If one of the girls had scored 6 points more, the average score of the group would have been 22

The table above shows the distribution of the distance, rounded to the nearest integer, run by 20 athletes in a marathon. Which of the
following cannot be the approximate average (arithmetic mean) distance run (in kilometres) by the athletes in the marathon?