Ch 13- Difference Analysis

Question 1

when comparing differences what does the researcher compare when dealing with nominal vs scale variables

Answer 1

A nominal variable requires that the researcher compare percentages; a scale variable requires comparing means. As you know by now, the formulas differ depending on whether percentages or means are being tested

Question 2

What is meant by “statistical significance of differences”? How does this notion underpin market research?

Answer 2

The differences must be statistically significant. As you know, the notion of statistical sig-nificance underpins marketing research. To be useful to the marketing researcher or manager, differences must be meaningful as well as statistically significant. Statistical significance of differences means that the differences found in the sample(s) truly exist in the population(s) from which the random samples are drawn.

Question 3

What are differences, and why should market researchers be concerned with them? Why are marketing managers concerned with them

Answer 3

market segmentation holds that different types of consumers have different wants and requirements, and these differences can inform marketing strategies. The needs and requirements of each of these market segments differ greatly from the others, and an astute marketer will customize his or her marketing mix to each target market’s unique situation.

Question 4

what is a meaningful difference ?

Answer 4

A meaningful difference is one that the marketing manager can potentially use as a basis for marketing decisions.

Question 5

what are meaningful, actionable and stable differences ?

Answer 5

A meaningful difference is one that the marketing manager can potentially use as a basis for marketing decisions. differences must be stable and actionable. stable differences are not short term or transitory. actionable differences are ones in which you can use elements of the marketing mix to target those differences.

Question 6

when to use a t test or a z test?

Answer 6

a t test is used for smaller samples 30 or less. a z test is used for a sample size of 30 or more.

Question 7

statistical significance in data analysis ?

Answer 7

they are identified as significance and probability. sometimes abbreviated as sig. or prob on the output. look at the umber associated with it, sometimes low as 0.000 and high as 1.00 As we noted previously, the significance or probability values reported in statistical analysis output range from .0000 to 1.000, and they indicate the degree of support for the null hypothesis (no differences). If you take 1 minus the reported significance level—for example, if the significance level is .03, you take 1 minus .03 to come up with .97, or 97%—this is the level of confidence for our finding. anytime the value is 95% or higher you have a green light to pass. because we are working with a 95% level of confidence.

Question 8

the null hypothesis in difference testings?

Answer 8

With a differences test, the null hypothesis states there is no difference between the percentages (or means) being compared. we test the null hypothesis, which is the hypothesis that the difference in their population parameters is equal to zero. The alternative hypothesis is that there is a true difference between them.

Question 9

what are independent samples?

Answer 9

Independent samples are treated as representing two potentially different populations

Question 10

Formula for significance of the difference between two percentages ?

Answer 10

Question 11

what is the computation of significance of two percentages ?

given:

p1=65%

p2=40%

n1= 100

n2=300

Answer 11

Question 12

HOW TO USE SPSS FOR DIFFERENCES BETWEEN PERCENTAGES OF TWO GROUPS ?

Answer 12

spss does not perform the tests, but it provides the relevant information so you can perfome it by hand. p1,p2,n1,n2.

and you can calculate q1, and q2 by using the p1+q1 =100

so p1-q1

Question 13

at a 95% confindence level when is the null hypothesis supported ?

Answer 13

when the computed z value falls between -1.96 and +1.96.

1 - 0.95%=0.05

0.05= Z 1.96

if this is the case then there is no signicant difference and the null hypothesis is accepted at a 95% confidence intereval. meaning is the test is repeated many times we get the same result 95% of the time.

Question 14

formular for calculating differences between two means ?

Answer 14

the formular is identical to the differences in two percentages, exceptht the standard error include the standard deviation of both poulations.

Question 15

what is ANOVA ?

Answer 15

Anova is also known as the Analysis of variance.

it is used to compare the means of three or more groups.

anova will signal when a pair of groups have significant differences. basically ach mean is compared with each other and the ones that show significant differences through anova are then looked at further. its basically a green/red light whether a marketer should proceed.

Question 16

ANOVA example ?

Answer 16

lets say we three groups A,B,C

anova compares

A:B

A:C

B:C

it makes these comparisons simutneously and displays a sig value for the comparisons. which is our signal light. if its less that 0.05 then you have a green light that there is significant difference.

Question 17

whats the difference between two means with the same smaple ? ( paired sample)

Answer 17

two means from two different questions answered by the same sample are they significantly different. the questions have to be measured using the same scale otherwise they are not comparable.

theres no formular but when looking t the spss output pay attention to the means displayed, the number of participants the t value and the sig (prob). if the sig (prob) is less than 0.05 then there is a difference between the two means and the null hypothese is rejected.

Question 18

what are the 4 differences tests outlined and their null Hypothesis ?

Answer 18