Question

Use the CardioGoodFitness data.

The company sells three different lines of treadmills. The TM195 is an entry-level treadmill designed for those who want minimal programs and the desire for simplicity to initiate their walk or hike.

The TM498 is a middle-line model for those who are in a transitional stage from walkers to running or midlevel runners. It has two programs and a 15% elevation upgrade from the TM195.

The TM798 is the top-of-the-line treadmill which is structurally larger and heavier and has more features than the other models. It is designed for those who are power walkers or runner.

• Go to the data sets in textbook. Use Cardio Good Fitness. • Click on STAT.
• T Stats → One Sample → With Data
• Select the appropriate column variable

• Select Product under Group by
• Under Perform, select Confidence interval for μ and set the level at 0.95. • Click Compute!
• The confidence interval is given by the L. Limit and U. Limit.

For marketing purposes, we want to estimate the mean age, income, and mileage for each model treadmill.

Calculate the 95% confidence interval for each variable grouped by the Treadmill model. Copy your results below.

Group by: Product
μ : Mean of Age

95% confidence interval results:

Product	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
TM195	28.55	0.80738286	79	26.942945	30.157055
TM498	28.9	0.85789784	59	27.18335	30.61665
TM798	29.1	1.1023285	39	26.87033	31.32967

Group by: Product
μ : Mean of Income

95% confidence interval results:

Product	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
TM195	46418.025	1014.7034	79	44398.308	48437.742
TM498	48973.65	1117.2252	59	46738.087	51209.213
TM798	75441.575	2926.0297	39	69523.121	81360.029

Group by: Product
μ : Mean of Miles

95% confidence interval results:

Product	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
TM195	82.7875	3.2282227	79	76.361883	89.213117
TM498	87.933333	4.2942523	59	79.340554	96.526112
TM798	166.9	9.4973546	39	147.68979	186.11021

Use these results to answer the following questions:

1. The TM195 sells for $1500, the TM498 sells for $1750, and the TM798 sells for $2500. Based off your results, are these prices reasonable? Explain.

2. Do we need to market the different models to different age groups? Explain.

3. Does there seem to be any differences in the amount of average miles for each model of treadmill? Explain.

Answer 1

Use these results to answer the following questions:

1. The TM195 sells for $1500, the TM498 sells for $1750, and the TM798 sells for $2500. Based on your results, are these prices reasonable? Explain.

For this you can refer below table, here the income for TM195 model and TM498 model has a lesser difference compared to the model TM798, it has almost 10 times income difference compared to other 2 models. Hence the price for model TM798 should be revised.

Group by: Product
μ : Mean of Income

95% confidence interval results:

Product	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
TM195	46418.025	1014.7034	79	44398.308	48437.742
TM498	48973.65	1117.2252	59	46738.087	51209.213
TM798	75441.575	2926.0297	39	69523.121	81360.029

Do we need to market the different models to different age groups? Explain.

No. Because if we check the table of Mean of Age. the average age for all 3 model is approximately 29 years.Hence we do not need to market different ages for different models.

Does there seem to be any differences in the amount of average miles for each model of treadmill? Explain.

Yes. There is a difference in a amount of mileage for each models. If you refer the table below:

Group by: Product
μ : Mean of Miles

95% confidence interval results:

Product	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
TM195	82.7875	3.2282227	79	76.361883	89.213117
TM498	87.933333	4.2942523	59	79.340554	96.526112
TM798	166.9	9.4973546	39	147.68979	186.11021

Here if you look at the Sample mean column, TM195 and TM498 models doesn't have much difference in mileage, however TM798 has a big difference almost double the mileage compared to two models above.