Central tendency and variability

Measures of Central Tendency

100

This measure describes the center or typical value of a data set.

Measures of Central Tendency

200

What are the 3 measures of central tendency?

Mean, median and mode

300

This measure is obtained by arranging the data in order and locating the middle value.

Median

400

This measure appears more frequently in the data set and it is used for nominal data. 

Mode

500

Which central tendency is most affected by outliers?

Mean

Measures of Variability

100

This concept describes how spread out or scattered the data values are.

Measures of Variability

200

What does the symbol σ represent?

Standard deviation 

300

This measure of variability is computed as the difference between the highest and lowest values.

Range 

R=HV-LV

400

This formula ∑|x-x̅|/n is used to find the ________ of a data set.

Mean deviation

500

This formula ∑(x-x̅)² /n is used to find the ________ of a data set.

Standard Deviation

Calculations (Measures of Central Tendency)

100

What is the mode? 

3, 4, 5, 7, 3

3

200

Find the median of the data set:
5, 4, 9, 1, 2

4

300

Find the mean of the data set:
4, 6, 10, 12

8

400

Find the mean of the following scores: 6, 8, 10, 12, 14.

mean: 10

500

Four numbers have a mean of 10. Three of the numbers are 8, 11, and 9. What is the fourth number?

12

Calculations (Measures of Variability)

100

Find the range of the data set:
2, 5, 1, 6, 10

9

200

What is the range of the data: 45, 50, 55, 60, 70?

25

300

If the variance is 9, what is the standard deviation?

σ=3

400

Find the mean deviation of the following data set:

3,6,9

MD=2

500

Find the standard deviation of the following data set:

1, 7, 9, 15

σ=5

Random

100

You have a bimodal distribution. How many modes do you have?

2 

200

You are studing favorite color. What scale of measurement is this. What central tendency is most apporpriate?

Mode: Always for nominal data

300

The scores of 5 students in a game are: 5, 7, 3, 6, 4. What is the average score?

mean=5

400

A teacher randomly selected 5 students from Class A and another 5 students from Class B to take a 100-item examination. The results are as follows: 

CLASS            SCORES           MEAN       SD

   A           80,85,85,90,95         87        5.70

   B.          65,80,95,95,100       87       14.40

If you were to decide which class performed better, who will it be and why?

Class A performed better since their scores are less disperse which was supported by the computed standard deviation.

500

A set of data consists of five numbers. The mode is 2. The median is 3. The mean is 4. The difference between the largest and smallest numbers is 6. What are the five numbers?

2,2,3,5,8