PFA

PFA


BUGEN1502: Assignment 2 Student name: Click or tap here to enter text. Student ID Number: Click or tap here to enter text. Please handed in only this word document. Be sure to include your name and student ID on this assignment Assignment 2: Confidence Interval and Hypothesis testing (10 marks) Background A researcher is interested in the average time for a package to arrive in Australia from a seller based in Hong Kong. The time is the days from the time of ordering to the time of arrival in Australia (in days). A random sample of the packages is selected. The data is saved in the Excel file BUGEN1502 Assignment 2 data.xls. Questions Question 1 (2 Marks) 1) Use Excel to obtain an appropriate histogram of the values of the arrival time. The interval in the table is to be used for creating the histogram. range Frequency 0 to 3 over 3 to 6 over 6 to 9 over 9 to12 over 12 to 15 over 15 to 18 over 18 to 21 over 21 to 24 over 24 to 27 over 27 to 30 over 30 Insert the histogram below Click or tap here to enter text. 2) Briefly state what the histogram is telling us about the distribution of the data. Click or tap here to enter text. 3) Calculate the descriptive statistics. Insert the descriptive statistics below Click or tap here to enter text. 4) Explain the distribution, central tendency and variation. Click or tap here to enter text. Question 2 (2 Marks) 1) Calculate the 95% confidence interval of the population mean, assume that the population standard deviation is known (σ = 5.80). Click or tap here to enter text. 2) Calculate the 95% confidence interval of the population mean, assuming that the population standard deviation is unknown. Click or tap here to enter text. Question 3 (4 marks) In the past it has been found that the arrival time have a population mean value of μ = 13 days. Assume that the population standard deviation is unknown. The significance level alpha is set at 5%. 1) The research wants to know whether this mean has changed. Test the hypothesis with the critical value approach. Click or tap here to enter text. 2) The research wants to know whether the mean is more than 13 days. Test the hypothesis with p value approach. Click or tap here to enter text. Question 4 (2 Marks) 1) Explain the meaning of p value. Click or tap here to enter text. 2) What is the advantage of p value approach over critical value approach? Click or tap here to enter text. 3) Does a small p value indicate a strong relationship between the studied variables? Give your reason. Click or tap here to enter text. 4) If a p value of a one tailed test is 0.04, what is the p value for a two tailed test? Click or tap here to enter text. Page 2 of 2