Aj Davis Course Project Parts a and B

1925 WordsOct 10, 20128 Pages
The following report presents a detailed statistical analysis of AJ DAVIS department store customers. Data was collected from a sample of 50 AJ DAVIS credit customers for the purpose of learning more about the customers of AJ DAVIS. The first variable considered is Location, a categorical variable. The three subcategories are Urban, Suburban and Rural. The frequency distribution and pie chart are included. Measures of central tendency and descriptive statistics are not calculated due to the categorical nature of the variable. Frequency Distribution: LOCATION | FREQUENCY | Urban | 22 | Suburban | 15 | Rural | 13 | The largest number of customers belong to the Urban Location category (44%), followed by those in the…show more content…
There is a linear positive relationship between Income and Credit Balance variables. Where income increases, credit balance also increases. The relationship between the variables Years and Credit Balance is illustrated in the following scatter plot: There is no clear relationship between the two variables in the scatter plot. The points are in no specific pattern, suggesting that there is no significant correlation between the variables years and credit balance. It can be concluded that some variables such as Income are strongly related to the credit balance of AJ DAVIS department store customers. Several other variables appear to be unrelated. PART B: Hypothesis Testing and Confidence Intervals 1.a- The average (mean) annual income was less than $50,000 I found the average (mean) income to be $43,740, with a standard deviation of $14,640. According to the hypothesis test (see appendix), the calculated test statistic of -3.0236 does fall in the rejection region of z<-1.645 therefore I can reject the null hypothesis and say there is sufficient evidence to indicate µ<50 or $50,000. The p-value of 0.001 (see appendix for data), supports the rejection of the null hypothesis since the p value is less than α=0.05. Based on the confidence interval, we can be 95% certain that the average income lies between $39,680-$47,800. 1.b- The true population proportion of customers who live in an urban area exceeds 40% Of those surveyed, 22 out of 50
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