Discovering Statistics Using IBM SPSS Statistics

Twenty-one cats were given 300g of tuna each. The time in seconds was measured until they had eaten all of the tuna:

16, 18, 18, 22, 22, 23, 23, 24, 26, 29, 32, 34, 34, 36, 36, 42, 43, 46, 46, 49, 57

• Compute the median.
• Compute the lower quartile.
• Compute the upper quartile.
• Compute the interquartile range.

Answer choices

1. 32 seconds         
2. 22.5 seconds     
3. 42.5 seconds     
4. 20 seconds

The owner of the large chain of coffee shops called ‘MoonBucks’ decided to calculate how much revenue was gained from lattes each month in a nationwide sample of 2445 cafés. To measure the variance of revenue gained from lattes, he computes SS = 351,936 for this sample.

• What are the degrees of freedom for variance?
• Compute the variance.
• Compute the standard deviation.

Answer choices

1. 144       
2. 12
3. 2444

An experimenter measured 30 children’s IQ. He then rank-ordered the children and assigned them a score from 30 (most intelligent) to 1 (least intelligent) to create a new variable. Does this new variable consist of: 

Answer choices

1. Nominal data    
2. Interval data      
3. Ratio data
4. Ordinal data

When items on a questionnaire appear to correspond to the construct that the questionnaire claims to measure it is said to have:

Answer choices

1. Factorial validity              
2. Ecological validity
3. Content validity
4. Criterion validity

Variation due to some genuine effect is known as:

Answer choices

1. Unsystematic variation  
2. Systematic variation
3. Homogeneous variance
4. Residual variance