Populations and Samples

Question 1

Population parameter

Answer 1

• any numerical quantity that characterises a given population or some aspect of it.
• tells us something about the whole population.

Question 2

Estimated Statistic

Answer 2

the process by which one makes inferences about a population, based on information obtained from a sample

Question 3

1. μ
2. σ
3. σ²
4. x̅
5. s
6. s²

Answer 3

1. Population mean
2. Population standard deviation
3. Population variance
4. Sample mean
5. Sample standard deviation
6. Sample variance

Question 4

Mean

Answer 4

addition of all values/number of samples

Question 5

Median

Answer 5

the middle score

Question 6

Mode

Answer 6

the most frequent score

Question 7

Range

Answer 7

highest value - lowest value

Question 8

Best measure of central tendency for nominal variables

Answer 8

mode

Question 9

Best measure of central tendency for ordinal variables

Answer 9

median

Question 10

Best measure of central tendency for interval/radial variables (not skewed)

Answer 10

mean

Question 11

Best measure of central tendency for interval/radial variables (skewed)

Answer 11

median

Question 12

Z-score

Answer 12

• a measure of how many standard deviations below or above the population mean a raw score is
• z = (X-x̅)/s

Question 13

Z-score curves

Answer 13

Leptokurtic:
- thin
- extreme points along the x-axis
- heavy tails
Mesokurtic
- normal
Platykurtic
- flat
- a distribution with negative excess
- light tails