Midterm: Unit 1-4

Question 1

What is the purpose of statistics in the behavioural and social sciences?

Answer 1

To summarize data and draw conclusions about behaviour and social phenomena.

Question 2

What are descriptive statistics?

Answer 2

Statistics used to summarize and describe the characteristics of a dataset.

Question 3

What are inferential statistics?

Answer 3

Statistics used to draw conclusions about a population based on sample data.

Question 4

What is a variable?

Answer 4

Any characteristic that can take different values across individuals or observations.

Question 5

What is a score?

Answer 5

A specific value of a variable for an individual.

Question 6

What is a frequency table?

Answer 6

A table that shows how often each value of a variable occurs.

Question 7

Why are frequency tables useful?

Answer 7

They make patterns in data easier to see and interpret.

Question 8

What is a histogram?

Answer 8

A graph that displays a frequency distribution using adjacent bars.

Question 9

How does a histogram differ from a bar graph?

Answer 9

Histogram bars touch because they represent continuous data.

Question 10

What does the shape of a distribution describe?

Answer 10

How scores are distributed across values.

Question 11

What is a unimodal distribution?

Answer 11

A distribution with one clear peak.

Question 12

What is a bimodal distribution?

Answer 12

A distribution with two distinct peaks.

Question 13

What is a symmetrical distribution?

Answer 13

A distribution where the left and right sides mirror each other.

Question 14

What is a positively skewed distribution?

Answer 14

A distribution with a long tail to the right.

Question 15

What is a negatively skewed distribution?

Answer 15

A distribution with a long tail to the left.

Question 16

What are the three representative values?

Answer 16

Mean, median, and mode.

Question 17

What is the mean?

Answer 17

The arithmetic average of a set of scores.

Question 18

What is the median?

Answer 18

The middle score when values are ordered.

Question 19

What is the mode?

Answer 19

The most frequently occurring score.

Question 20

Which measure is best for nominal data?

Answer 20

The mode.

Question 21

What is variability?

Answer 21

The degree to which scores differ from one another.

Question 22

What is the range?

Answer 22

The difference between the highest and lowest scores.

Question 23

What is variance?

Answer 23

The average of squared deviations from the mean.

Question 24

What is standard deviation?

Answer 24

The typical distance of scores from the mean.

Question 25

How do outliers affect variance and standard deviation?

Answer 25

They increase both measures.

Question 26

What is a Z score?

Answer 26

A standardized score indicating how far a value is from the mean.

Question 27

What does a positive Z score indicate?

Answer 27

A score above the mean.

Question 28

What does a negative Z score indicate?

Answer 28

A score below the mean.

Question 29

What is the formula for a Z score?

Answer 29

Z = (X − M) / SD

Question 30

What is the mean of a Z score distribution?

Answer 30

0

Question 31

What is the standard deviation of a Z score distribution?

Answer 31

1

Question 32

Why are Z scores useful?

Answer 32

They allow comparison across different scales.

Question 33

What does correlation measure?

Answer 33

The relationship between two variables.

Question 34

What does the correlation coefficient indicate?

Answer 34

The direction and strength of a linear relationship.

Question 35

What is the range of the correlation coefficient?

Answer 35

From −1.00 to +1.00.

Question 36

What does a positive correlation mean?

Answer 36

As one variable increases, the other increases.

Question 37

What does a negative correlation mean?

Answer 37

As one variable increases, the other decreases.

Question 38

What does a correlation of zero mean?

Answer 38

No linear relationship exists.

Question 39

What is a scatter diagram?

Answer 39

A graph showing the relationship between two variables.

Question 40

What is a curvilinear correlation?

Answer 40

A relationship that changes direction.

Question 41

Does correlation imply causation?

Answer 41

No.

Question 42

What are the three explanations for correlation?

Answer 42

X causes Y, Y causes X, or a third variable causes both.

Question 43

What is the coefficient of determination?

Answer 43

The proportion of variance explained by the relationship.

Question 44

How is the coefficient of determination calculated?

Answer 44

By squaring the correlation coefficient (r²).

Question 45

What is multiple regression?

Answer 45

Prediction of a dependent variable using two or more independent variables.

Question 46

What is a normal distribution?

Answer 46

A symmetrical, bell-shaped distribution.

Question 47

What are the characteristics of a normal curve?

Answer 47

Symmetrical, unimodal, mean equals median equals mode.

Question 48

What is the empirical rule?

Answer 48

68% within 1 SD, 96% within 2 SD.

Question 49

What does the normal curve table show?

Answer 49

Percentages of scores between the mean and Z values.

Question 50

What is probability?

Answer 50

The expected relative frequency of an outcome.

Question 51

What is the formula for probability?

Answer 51

Successful outcomes divided by total outcomes.

Question 52

What is a population?

Answer 52

The entire group of interest.

Question 53

What is a sample?

Answer 53

A subset of the population.

Question 54

What is random sampling?

Answer 54

Each population member has an equal chance of selection.

Question 55

Why is random sampling important?

Answer 55

It reduces bias and increases representativeness.

Question 56

What is the purpose of inferential statistics?

Answer 56

To draw conclusions about populations from samples.