2. Use the contingency table to the right to calculate marginal frequencies and find the expected frequency for each cell in the contingency table. Assume that the variables are independent.
Result Brand name Generic Placebo
Improvement 18 28 16
No change 24 20 49
a)Calculate marginal frequencies and sample size.
b)Find the expected frequency for each cell in the contingency table.
3. Use the confidence interval to find the margin of error and sample mean.
Mean=np=122*.29=35.38 or 35.4
Variance=np(1-p)=122*.29*(1-.29)= 25.1198 or 25.1
Standard deviation=square roof of variance=25.1198^0.5=5.01197 or 5.0
There are three problems. Solution to first problem depicts the formulas to find mean, variance and standard deviation of a binomial distribution. Solution to second problem explains the methodology to calculate marginal frequencies and expected frequency for cell in the contingency table. Solution to third problem calculates the sample mean and margin of error.
Basic Statistics Concepts and Hypothesis Testing
1. A mean score of 5.4 with SD of 1.6, where would 68% fall? a.between 3.8 and 7.0 or b.between 5.4 and 7.0?
2.Descriptive stats related to variabitity helps you evaluate what of a sample? a.the homogeneity or heterogeneity of the sample, b.the sampling error,c.the t test or d.meta analysis
3.is rating job satisfaction on 5 point scale 1=very satisfied, etc ordinal?
4.what does a SD of 3.73mean in terms of scores?
5. If the SD score was larger, how would you interpret the score in terms of homogeneity or heterogeneity of the sample? (study critical thinking in nursing students on a six item measure)
If females and males have mean score of 23 on critical thinking test but females had a SD of 7 and males of 3, what can you conclude about the males in terms of homogeneity of the sample?
6.what is a null hypothesis in a group a and group b(one gets flu shots and one nil)