t Test on SPSS

t Test on SPSS

Independent and Dependent t Test on SPSS

Do the following t tests on SPSS. You have been provided with the alternative hypothesis for each question to make the writeup easier. Take the alternative hypothesis and make the necessary changes to it for the results. Do not rewrite the statement, just add the extra information as instructed. Make sure that you double space your writeup. Remove the decimals from the data. Do not round the p values from the printouts.

  1. How much more would you expect to pay for a home that has four bedrooms than for a home that has three? The following are asking prices for homes in a city in the Midwestern part of the United States. At α = 0.05 is there a difference in the asking prices between 3 and 4 bedroom homes?

Four–Bedroom Homes

149,900           169,900           175,000           189,000           206,900           225,000

249,900           289,900           320,000           339,900           399,900           429,900

Three-Bedroom Homes

79,500                         82,000                         89,999                         90,000                         99,900                       100,000

106,900           189,900           219,900           260,000           274,900           295,900

Ha: There is a difference in asking prices between 3 and 4 bedroom homes.

  1. A major oil company would like to improve its tarnished image following a large oil spill. Its marketing department developed a short television commercial and tested it on a sample of 7 participants. People’s attitudes were measured with a short questionnaire, before and after viewing the commercial. At α = 0.05, did the commercial help to improve attitudes toward the oil company?

Before   15   11   10   11   14   10   11    

After      15   13   18   12   16   10   19

Ha: The television commercial helped in improving attitudes toward the oil company.

*Gravetter, F. J., &Wallnau, L. B. (2005). Essentials of statistics for the behavioral sciences (5thed.). Belmont, CA: Thomson, Wadsworth.

** Moore, D. S., McCabe, G. P., & Craig, B. A. (2012). Introduction to the practice of statistics (7thed.). New York, NY: W. H. Freeman.    

Solution 

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T-Test Ryan

[DataSet1]

Group Statistics
Home N Mean Std. Deviation Std. Error Mean
Price Four – Bedroom Homes 12 262100.00 93378.876 26956.160
Three – Bedroom Homes 12 157408.25 84459.912 24381.476
Independent Samples Test
Levene’s Test for Equality of Variances t-test for Equality of Means
F Sig. t df Sig. (2-tailed) Mean Difference Std. Error Difference 95% Confidence Interval of the Difference
Lower Upper
Price Equal variances assumed .027 .870 2.880 22 .009 104691.750 36346.815 29313.070 180070.430
Equal variances not assumed 2.880 21.782 .009 104691.750 36346.815 29269.296 180114.204

T-Test

[DataSet2]

Paired Samples Statistics
Mean N Std. Deviation Std. Error Mean
Pair 1 Before 11.71 7 1.976 .747
After 14.71 7 3.251 1.229
 

Paired Samples Correlations

N Correlation Sig.
Pair 1 Before & After 7 .167 .721
Paired Samples Test
Paired Differences t df Sig. (2-tailed)
Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
Lower Upper
Pair 1 Before – After -3.000 3.512 1.327 -6.248 .248 -2.260 6 .065

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  1. At α = 0.05, there is a statistically significant difference in the asking prices between three and four-bedroom homes in a city in the Midwestern part of the United States, with p-value of the two-tailed independent samples t-test = 0.009
  1. At α = 0.05, the short television commercial developed by the oil company significantly helped in improving people’s attitudes towards the oil company, with p-value of the one-tailed dependent (or paired) samples t-test = 0.0325 (0.065/2)