Week 9_Frequency Distribution, Cross Tabulations & Hypothesis Testing

Question 1

what is valid percentage for frenquency of distribution?

Answer 1

exclude missing response

Question 2

Which mesurement is most commn used of central tendency?

Answer 2

Mean value

Question 3

The mode value is good for which usage?

Answer 3

The mode is a good measure of location when the variable is inherently categorical or has otherwise been grouped into categories.

Question 4

What skewness can do?

Answer 4

the tendency of the deviations from the mean being larger in one direction than in the other. It can be thought of as the tendency for one tail of the distribution to be heavier than the other.

Question 5

What is Kurtosis

Answer 5

a measure of the relative peak or flatness of the curve defined by the frequency distribution.

Question 6

Features of Kurtosis of

Answer 6

– The kurtosis of a normal distribution is zero.
– If the kurtosis is positive, then the distribution is more
peaked than a normal distribution.
– A negative value means that the distribution is flatter than a normal distribution.

Question 7

What is null hypothesis

Answer 7

=no difference or no effect. if no reject, no change

Question 8

What is alternative hypothesis?

Answer 8

some difference or effect is expected. Accepting the alternative hypothesis will lead to changes in opinions or actions.

Question 9

What is cross-tabulation analysis?

Answer 9

wo categorical variables are arranged in a cross-tabulation table (a table in which data are compared using a row-and-column format).

Question 10

The Cross-tabulation table only depicts the two variables simultaneously; it is NOT a statistical test.

Answer 10

True

Question 11

What is Chi-square?

Answer 11

examination of frequencies for two categorical variables in a cross-tabulation table to determine whether the variables have a significant relationship.

Question 12

Chi-square (𝜒2) analysis is a statistical test

Answer 12

True

Question 13

How to calculate Chi-square?

Answer 13

lump sum of (observe frequency - expected frequency)/expected frequency

Question 14

How to calculate expected frequency?

Answer 14

Cell column total*Cell row total/grand total

Question 15

How to calculate degree of freedom in Chi-square?

Answer 15

(Number of rows - 1)*(Number of column - 1)

Question 16

The relationship between critical table value and chi-square value

Answer 16

if chi-square value is bigger than critical table value, which means null-hypothesis (no significant relationship between two variables) is rejected and there is a significant relationship between two variables.

Question 17

How to get critical table value?

Answer 17

Base on degree of freedom, check chi-squaire distribution and get the table value.

Question 18

Chi-square value > critical table value, then null-hypothesis is not support, then alternative hypothesis is accepted.

Answer 18

True

Question 19

What is meaning of reject null-hypothesis?

Answer 19

Accept alternative hypothesis and show changes and difference.

Question 20

Two classification of hypothesis tests

Answer 20

Test of association and test of difference

Question 21

How to formulate hypothesis?

Answer 21

In marketing research, null hypothesis is formulated in such a way that its rejection leads to the acceptance of the desired conclusion
For example, if you want to numbers of online shopping bigger than 40%, then you set null hypothesis H0 <40%， Alternative hypothesis H1 >40%

Question 22

How to express hypothesis if research involve proportion?

Answer 22

Two-tailed test required and hypothesis will be expressed as H0=40% H1 not = 40%

Question 23

Different between t test and z test

Answer 23

sample numbers

Question 24

What is type one error?

Answer 24

when the sample results lead to the rejection of the null hypothesis when it is in fact true.

Question 25

What is type two error?

Answer 25

when, based on the sample results, the null hypothesis is not rejected when it is in fact false.

Question 26

What is level of significance?

Answer 26

Depends on different situation, choose type one error or type to error.

Question 27

What value for probability of type one error?

Answer 27

0.05

Question 28

What value for probability of type two error?

Answer 28

depends on the actual value of the population parameter (mean or proportion).

Question 29

What is power of test?

Answer 29

probability (1 − β) of rejecting

the null hypothesis when it is false and should be rejected

Question 30

The probability associated with the calculated or observed value of the test statistic is 0.0301 (this is the probability of getting a p value of 0.567 when π = 0.40).
This is less than the level of significance of 0.05. Hence, the null hypothesis is rejected.

Answer 30

True

Question 31

• Parametric tests assume that the variables of interest are measured on at least an interval scale.
• Nonparametric tests assume that the variables are measured on a nominal or ordinal scale.

Answer 31

True

Question 32

Parametric test

Answer 32

The variable is normally distributed and the mean is known (or assumed to be known) and the population variance is estimated from the sample.

Question 33

Calculated value greater than table value, null hypothesis is rejected.

Answer 33

true

Question 34

The relationship between K value and decision of null hypothesis rejection.

Answer 34

The larger K is, the more confidence we have that H0 is false
K=critical table value/n^2

Question 35

If p value <0.05 (95% confidence level) there is significant difference

Answer 35

True