Statistics

Question 1

Formula to count multiples in a set of consecutive integers

Answer 1

k is the number that have to find multiples of

largest # of k in set - smallest # of k in set / K + 1

To calculate the total number of multiples of A or B, we can use the following formula:

The number of multiples of A or B = the number of multiples of A + the number of multiples of B - the number of multiples of LCM(A, B)

Question 2

Counting the Multiples of Integer A or B, but Not of Both, in a Set of Consecutive Integers

Answer 2

The number of multiples of A or B but not of both = the number of multiples of A + the number of multiples of B - 2(the number of multiples of LCM of A,B)

Question 3

weighted average formula

Answer 3

weighted average = (data point 1 x frequency of data point 1) + (data point 2 x frequency of data point 2)…etc/ Number of subjects

Question 4

How to find position of median in odd list of numbers

Answer 4

n+1/2 where n is the number of numbers

Question 5

how to find position of median in even list of numbers

Answer 5

find the average of the position of the two middle numbers

1. n/2
2. n+2/2

Question 6

What if there are no numbers in a set that occur the most times?

Answer 6

there is no mode

Question 7

finding mean / standard deviation with high and low ranges in a set

Answer 7

high value = mean + standard deviation * number of standard deviations

low value = mean - standard deviation * number of standard deviations

Question 8

Adding or subtracting the same value to or from all terms in a set does not change the standard deviation

Answer 8

Adding or subtracting the same value to or from all terms in a set does not change the standard deviation

Question 9

Multiplying or dividing the data set by the same factor does change the standard deviation

Answer 9

the standard deviation will be multiplied or divided by the amount changed

Question 10

Steps to compare standard deviation

Answer 10

1. Determine the mean of each set
2. For each individual set, determine the absolute difference between the mean of that set and each data point in that set
3. Sum the absolute differences obtained between each individual set

The set that has the largest sum has the greatest standard deviation

Question 11

When will the standard deviation go down?

Answer 11

When a number equal to the mean of the set is added

Question 12

When will the standard deviation in a set be 0?

Answer 12

When all the data points in the set are equal to the mean, in other words,if all the numbers in the set are the sam

Question 13

If the range in a set in 0, what do we know?

Answer 13

That 1) all the values in the set are the same and 2) that the standard deviation is 0

Question 14

When the largest or smallest value in a set is equal to the mean, what do we know?

Answer 14

That 1) all the values in the set are the same and 2) that the standard deviation is 0

Question 15

When all of the values in a set are not the same, what do we know?

Answer 15

The standard deviation is not 0.

Question 16

counting the number of consecutive integers in a set inclusive of either only the first or last number in a set, not both

Answer 16

last number - first number

Question 17

counting the number of consecutive integers in a set excluding the first and last number in a set

Answer 17

last number - first number - 1

Question 18

bookend method for finding the average of an evenly spaced set of numbers

Answer 18

first number + last number / 2

Question 19

balance point method

Answer 19

odd nnumber

Question 19

balance point method for finding the average of an evenly spaced set of numbers

Answer 19

odd numbers of integers:

• imagine the numbers on a line
• the number in the middle is the average

even numbers of integers:
- imagine the numbers on a line
- the average of the two middle terms is the average of the set

Question 20

sum of integers formula

Answer 20

sum = n(first + last integer)/2