Introduction to statistical reasoning

Question 1

What is meant by theories and hypotheses being in the conceptual domain?

Answer 1

You cannot observe them directly

Question 2

Explain why a hypothesis is not simply a prediction

Answer 2

An explanatory statement about something that is not yet observable. The prediction is not the hypothesis, it is something derived from the hypothesis that operationalises it so that you can observe things that let you determine the plausibility of the hypothesis

Question 3

Give other words for predictor and outcome variables

Answer 3

Predictor- independent

outcome- dependent

Question 4

What is meant by a nominal variable?

Answer 4

A variable made up of different categories

Question 5

What is an ordinal variable?

Answer 5

The categories are put in a certain order (concentrations of a liquid)

Question 6

What is interval data?

Answer 6

Numerical data given in intervals where each equal interval on the scale represents equal differences in the quality being measured (likert scale)

Question 7

How does ratio data differ from interval data ?

Answer 7

the ratios of the values along the scale should be meaningful. For this to be true the scale must have a true and meaningful 0 point ( 2 should be half as effective as 1 when rating a product)

Question 8

What is meant by a continuous variable?

Answer 8

A variable that can be measured to any level of precision

Question 9

What is meant by criterion validity?

Answer 9

Whether you can establish that an instrument measures what it claims to measure through comparison to objective criteria

Question 10

What is a within subject design?

Answer 10

When the same subjects are all given the various conditions

Question 11

What is a between subjects design?

Answer 11

Different subjects take part in each condition

Question 12

How can carry on effects of a repeated-measures design be negated

Answer 12

Counter-balancing the order the conditions come in

Question 13

What does it mean for a graph to be positively skewed?

Answer 13

Skewed to the right

Question 14

What is meant by kurtosis?

Answer 14

The degree to which scores cluster at the end of the ends of the distribution

Question 15

What would it mean for a graph to have a positive or negative kurtosis?

Answer 15

Positive- many score at the tails and is pointy

negative-relatively thin in the tails and tends to be flatter than normal

Question 16

What other names are given to graphs with negative and positive kurtosis?

Answer 16

Positive- leptokurtic

Negative-Platykurtic

Question 17

What are the values of skew and kurtosis in a normal distribution?

Answer 17

0

Question 18

Find the dispersion of this data set

12, 36, 37, 48, 56, 72

Answer 18

72- 12 = 60

Also known as the range

Question 19

When there is extreme outliers what is done with the range?

Answer 19

Interquartile range- chop off the outside 25% both sides

Question 20

Give another name for the second quartile

Answer 20

Median

Question 21

Where is the second and third quartile located?

Answer 21

Middle of lower and upper halves of the data

Question 22

What are quantiles?

Answer 22

Values that split the data in equal portions

Question 23

What are the APA guidelines when deciding how to present your data? (4)

Answer 23

> Choose a mode of presentation that optimises the understanding of the data
3 or fewer numbers try use a sentence
4 and 20 consider a table
20 and above a graph is usually more useful

But use common sense

Question 24

How many decimal places should usually be utilised?

Answer 24

As few as possible ( m, cm, mm example ) but maintain accuracy