Foundation of Data Analytics

Question 1

Parameter Def.

Answer 1

Value of a variable that characterises a population

Question 2

Statistics Def.

Answer 2

Value of a variable that characterises a sample

Question 3

Population Parameter Examples

Answer 3

Mean (mew) and standard deviation

Question 4

Sample Parameter Examples

Answer 4

Mean (x bar) and standard error

Question 5

Probability Sampling Def.

Answer 5

Every member of population has a known chance of being selected. Warrants better representation

Question 6

Sampling Bias

Answer 6

Some members of a population are systemically more/less likely to be chosen. Forms a biased sample

Question 7

Uniform Occurrence

Answer 7

All variables are equally likely to be chosen

Question 8

Sampling Distribution Def.

Answer 8

Compilations of means of different samples across a population. The mean of a sampling distribution curve should be close to population mean. Always normally distributed. Gives support for inferences from sample to population

Question 9

Statistical Dispersion Def.

Answer 9

Fluctuations in means in samples of the same population. Caused by sample size (bigger N = lower fluctuation) and original population variation/outliers (smaller sd = smaller variations)

Question 10

CLT States

Answer 10

Sample mean should be similar to pop mean, standard error should be smaller then standard deviation and sample means will alwys be normally distributed (and the mean of the sampling distribution should be equal to pop mean)

Question 11

Standard Error Relationship To Accuracy of sample to pop representation

Answer 11

Large standard error = sample mean is inaccurate representation of true pop parameter

Question 12

Random Variation

Answer 12

How unexpalanable variation can be accounted for and modeled. May be produced via observation through random sampling

Question 13

What is sampling error based on sampling distribution

Answer 13

Estimates random sampling error

Question 14

Interval Estimates

Answer 14

Select a range of values that could hypthetically be the pop mean

Question 15

Point Estimate

Answer 15

Selecting 1 value to hypothetically be pop mean

Question 16

95% confidence intervals

Answer 16

Assuming that 95% of samples include pop mean (through sample mean or standard error). Gained by cutting 2.5% off your data at either end (remove outliers)

Question 17

Normal Curve Def

Answer 17

Graph form that helps describe errors in measurement

Question 18

How is probability of occurrence measured

Answer 18

Area under curve

Question 19

Z scores

Answer 19

A form of standardising scales. Standardising standard deviation