Question 16 A survey of 25 randomly selected customers found the ages shown (in years). The sample mean is 38.16 years, and the sample standard deviation is 8.91 years. The Lower Confidence Limit (LCL) for a 90% Confidence Interval for the population mean is: 35.81 35.23 35.11 41.09 Question 17 Partial Excel output from another random sample of 10 observations: Coefficients Standard Error 9.795 3.508 0.681 0.319 Intercept Number of salespeople working (x) Lower Confidence Limit for 80% Confidence Interval for the slope is: 0.235 0.087 -0.055 0 -0.244 Question 18 For obtaining a 90% Confidence Interval for the difference of the means of two normal populations, two random samples, one from each population, both of the same size 10, were drawn. For the first sample, sample mean = 27, and sample standard deviation = 13.33. For the second sample, sample mean = 40, and sample standard deviation = 28.11. Assuming unequal variances for the two populations, using 18 degrees of freedom (from technology), the Margin of Error ME for the Confidence Interval is: 0 26.95 18.875 10.799 17.06 Question 19 A website that rents movies online recorded the age and the number of movies rented during the past month for some of their customers. The data are shown below for a random sample of 23 of their customers. The regression line for the data, with number of movie rentals as the response variable, provides an intercept = 19.84, and slope = -0.293. The standard error of the slope SE(b1) = 0.1087. Margin of error ME for a 80% Confidence Interval for the slope of the Population regression line is: 0.2157 0.1438 0.0719 0.2876 Question 20 Partial Excel regression output from another random sample of 10 observations Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Intercept 9.795 3.508 Number of salespeople working (x) 0.681 0.319 To test the hypotheses Ho: = 0 versus HA: = 0, the P-value of the test, based on the computed t-Stat value, is: 0 Less than 0.025 Between 0.025 and 0.05 Between 0.05 and 0.1 More than 0.1