1.1

Question 1

Histograms help us to identify:

Answer 1

1. The shape of the distribution
   • Skew (the mode of the distribution is either on the left (-> positive skew) or on the right (negative skew))
   • Kurtosis (when your distribution is very pointy)
   • Spread or variation in scores
2. Unusual scores

Question 2

Histograms plot:

Answer 2

• The score (x-axis)

* The frequency (y-axis)

Question 3

Boxplots are made up of

Answer 3

a box and two whiskers

Question 4

The box shows:

Answer 4

• The median
• The upper and lower quartile
• The limits within which the middle 50% of scores lie.

Question 5

The whiskers show

Answer 5

• The range of scores

* The limits within which the top and bottom 25% of scores lie

Question 6

Median

Answer 6

The middle score when scores are ordered

Question 7

The Range

Answer 7

The smallest score subtracted from the largest

Question 8

Interquartile Range

Answer 8

• The three values that split the sorted data into four equal parts.

• Second quartile = median.
• Lower quartile = median of lower half of the data.
• Upper quartile = median of upper half of the data.

Question 9

Mean

Answer 9

The sum of scores divided by the number of scores.

Question 10

Bar charts

Answer 10

1. The bar (usually) shows the mean score

2. The error bar sticks out from the bar like a whisker.

Question 11

Hypothesis

Answer 11

Statement of causal and effect

• Independent variable
• Dependent variable

Question 12

Independent Variable

Answer 12

• The proposed cause
• A predictor variable
• A manipulated variable (in experiments)
• X variable

Question 13

Dependent Variable

Answer 13

• The proposed effect
• An outcome variable
• Measured not manipulated (in experiments)
• Y variable

Question 14

Bar charts

The error bar displays the precision of the mean in one of three ways:

Answer 14

• The confidence interval (usually 95%)
• The standard deviation
• The standard error of the mean