Measures of Location

Question 1

How do you calculate the mean for individual observations?

Answer 1

1. Add up all the numbers

2. Divide the total by how many numbers there are

Question 2

How do you calculate the mean for non-grouped data?

Answer 2

1. Times the age by frequency
2. Add up what you just calculated
3. Add all of the frequencies together

Divide:
The sum of age x frequency / frequency

Question 3

How do you calculate the mean for non-grouped data, using a calculator?

Answer 3

1. Shift - Mode - Stat - Freq ON
2. Mode - Stat - 1-Var
3. Shift - 1 - Variable - XBAR

Question 4

How do you calculate the mean for grouped data?

Answer 4

1. Find all the midpoints: NOTE: if the groups have a less than sign, then you need to use the number below that, e.g. its it 0 to less than 10, you need to use 9 to calculate the midpoint
2. Times the midpoints by the frequencies and then add them all up to give a total
3. Add all of the frequencies together

Divide:
Midpoints x frequency total / frequency total

Question 5

How do you calculate the medium for individual observations?

Answer 5

1. Sort out the observations from highest to lowest

2. Find the middle value

Question 6

How do you calculate the medium for non-grouped data?

Answer 6

1. Get the cumulative frequencies: add up the frequencies down the line
2. Add 1 to the cumulative frequency total / by 2
3. Find where the value lies on the number you just identified

Question 7

How do you calculate the medium for grouped data?

Answer 7

1. Get the relative cumulative frequencies:
   - Relative frequency: frequency / total frequency
   - Add up these values as you go down
2. Draw a graph with the relative cumulative frequencies on the Y axis and the other variable on the X axis
3. Plot the relative cumulative frequencies over the end of each interval
4. Plot the cumulative relative frequency of the group that the numbers median within

Question 8

What does a positive skew look like?

Answer 8

Highest bars are to the left

Question 9

What does a symmetric skew look like?

Answer 9

Bars are even around the middle

Question 10

What does a negative skew look like?

Answer 10

Highest bars at the right

Question 11

Where are the mean/medium/mode in relation to one another when the skew is positive?

Answer 11

Mode, median, mean

Question 12

Where are the mean/medium/mode in relation to one another when the skew is negative?

Answer 12

Mean, median, mode

Question 13

Where are the mean/medium/mode in relation to one another when the skew is symmetric?

Answer 13

All in the middle, inline