Univariate statistics

Question 1

What is the difference between descriptive and inferential statistics?

Answer 1

• Descriptive summaries Dara, while inferential statistics make predictions or generalisations about a population from a sample

Question 2

What are sample statistics and population parameters?

Answer 2

Sample statistics are measures from sample data, population parameters are measures from the entire population

Question 3

What is a frequecy distribution?

Answer 3

A table summarising how often each value of a variable occurs

Question 4

What is a percentage distribution?

Answer 4

• A frequency distribution that expresses values as percentages

Question 5

What does probability refer to in statistics?

Answer 5

The long run relative frequency with which an event will occur

Question 6

What is a deviation score?

Answer 6

The difference between an obseravtion and the mean of the data base

Question 7

What determines which statistics are appropriate to use?

Answer 7

The type of scale used e.g nominal, ordinal, interval, ratio

Question 8

What is normal distribution?

Answer 8

A symmetrical, bell shaped curve representing the expected distribution of many natural variables

Question 9

What is standard normal distribution?

Answer 9

A normal distribution with a mean of 0 and a standard deviation of 1

Question 10

What is the Z-value used for?

Answer 10

To standardize values and find the probability of occurenece under the normal curve

Question 11

What is the central limit theorem?

Answer 11

• A sample size increases, the distribution of sample means approaches a normal distribution, regardless of the original distribution’s shape.

Question 12

What is a confidence interval estimate?

Answer 12

• A range around a sample mean that is likely to contain the population mean