Week 3

Question 1

What are inferential statistics

Answer 1

Used to make inferences (statements/conclusions) about the true state of affairs in the population

Question 2

What is central tendency

Answer 2

The central tendency of a distribution of scored can be regarded as typical, representative or the middle score in the disctribution

Question 3

What is dispersion

Answer 3

dispersion means variability i.e., the extent to which a central value can be stretched out or squeezed in or how much a data is likely to vary around an average value. This concept of dispersion in statistics helps in the understanding of the distribution of data.

Question 4

What is the mean and how is it calculated

Answer 4

Mean in statistics refers to the average of a collection of values. The collection of values can be two or more. The sum of a collection of numbers is divided by the number of numbers in the collection.

Question 5

What is the mode

Answer 5

The mode is the value that appears most frequently in a data set

Question 6

What is the median and how is it calculated

Answer 6

The median is the middle number in a sorted, ascending or descending list of numbers and can be more descriptive of that data set than the average. To determine the median value in a sequence of numbers, the numbers must first be sorted, or arranged, in value order from lowest to highest or highest to lowest

Question 7

What are the features of a normal distribution

Answer 7

Bell shaped curve, symmetrical, has precise mathematical shape

Question 8

What is the central limit theorem

Answer 8

states that the distribution of a samplevariable approximates a normal distribution (i.e., a “bell curve”) as the sample size becomes larger, assuming that all samples are identical in size, and regardless of the population’s actual distribution shape.

Question 9

What is a Z score

Answer 9

A Z-score is a numerical measurement that describes a value’s relationship to the mean of a group of values

Question 10

What does a positive Z score mean

Answer 10

Indicates the score is the above the mean

Question 11

What does a negative Z score mean

Answer 11

Indicates the score is less than the mean

Question 12

Why do we need Z scores

Answer 12

Allows for comparison between populations, samples

Question 13

What is a parameter

Answer 13

A number that describes the data from a population

Question 14

What is a statistic

Answer 14

A number that describes the data from a sample. Eg means and standard deviations (SD)

Question 15

What does frequency refer to

Answer 15

The number of times an event occurs

Question 16

What is experimental relative frequency

Answer 16

The amount of times an event is expected to occur if the experiment was repeated many times

Question 17

What are nominal variables

Answer 17

Generate frequency data and are used for categorical variables with qualitatively different categories. Eg boys 1, girls 2

Question 18

What are ordinal vairables

Answer 18

Rank order scales, They have categories that could be ranked ordered along a continuum. Eg rate experience from -10

Question 19

What are interval variables

Answer 19

Those in which the intervals between adjacent markers are assumed to be equivalent

Question 20

What are ratio variables

Answer 20

a quantitative variable that can be used to measure a concept on a scale that has a meaningful zero point. For example, if we were interested in measuring the level of economic development in different countries, we could use the ratio variable of Gross Domestic Product (GDP) per capita.

Question 21

Are interval and ratio variables considered parametric or non-parametric

Answer 21

Parametric

Question 22

What is the formula to calculate probaility

Answer 22

P= the number of all possible successful outcomes VS the number of all possible outcomes

Question 23

What is statistical significance

Answer 23

The probability that an obtained statistical value is the result of chance alone

Question 24

What is the P value

Answer 24

Tells us how likely it is to get a result like this if the hypothesis is true