Question

Please answer these questions using SPSS. Thank you

Note: For all assignments, you must show the requested output from SPSS.

Example. Determine the descriptive statistics for three quantitative variables. Which variable has the highest mean? The most variability?

Answer: Output should include 3 boxes of descriptive statistics, one for each variable. There should also be one page that gives the answer to the other two questions.

The following sample data are used. We are interested in the descriptive statistics from these variables: sleep duration of undergrads, the number of NBA wins and the number of words in a résumé). Assume that they are all samples from populations. Use the instructions from the first two recitation worksheets to help you.

Sleep duration for undergraduates (minutes)		Wins2 (NBA teams)	Words3 (in résumé)
405	388	60	190
367	475	53	339
368	425	50	220
373	425	49	295
376	535	46	180
410	580	41	214
379	383	40	257
383	440	38	201
385	488	38	242
387	523	22	240
400		28	223
390		32	301
425		25	267
488		53	284
523		48	238
600		67	251
420		56	278
488		56	294
488		51	266
523		55	227
328		55	281
367		50	312
368		45	332
390		45
376		39
377		38
379		30
383		29
385		21
400		16
	N = 40	N = 30	N = 23

¹ This is a survey of the amount of sleep for one night for 40 undergraduates.

² These are the numbers of wins for the 30 National Basketball Association teams for the 2014-2015 NBA season.

³ A large university offers training on résumé construction. This lists the number of words in each of 23 résumés.

Note: Here are the 5% Trimmed Means for these variables. This will help you make sure you’ve input the data correctly: Amount of sleep: 419.94 minutes. Wins: 42.69. Words: 257.72.

1. Input the data the way you learned in recitation. You can input all of the data (3 data sets) at the same time, but you must run the analysis of each variable individually, otherwise SPSS won’t read it correctly, because the sample sizes are different. [Compare your descriptive statistics with the means and standard deviations on your graphs; this will help you make sure100405405 your numbers are correct.] In addition, I want you to add another variable next to the words variable which will divide the variable “Words” categorically. I want you to call this variable “wordscat.” (Note: this is the variable name. The variable labelcan be more descriptive, e.g., Words by Category). Create this variable using the Transform procedure you used in lab. Remember that you will have to give this variable Value Labels in the Variable View.

The scores should be divided into categories like this:

Low: 100-200              Moderate: 201-300           High: 301-400

2. For all the quantitative variables (wordscat is categorical) find descriptive statistics (using Explore). Print out “Descriptives” and Stemplot. Remember to do this for each variable individually. If you try to do them at the same time your answers will be incorrect.

3. For all the quantitative variables (wordscat is categorical) create and print out frequency distributions and histograms (using Frequencies). Remember to do this for each variable individually. If you try to do them at the same time your answers will be incorrect. Note: When doing the histogram, if you check the box “Show Normal Curve” this does not mean your variable is normal. It just shows what normal would look like and you can compare the shape of your variable to what is normal.

4. For the categorical variable (wordscat) create and print out a bar chart. Make sure the variable is categorical on your chart and remember to label the chart.

5. Create a variable (call it “sleeptwo”) that multiplies each student’s amount of sleep by 2 (do this by using Transform > Compute like in Lab 2, but instead of adding, we are multiplying by 2. Use this sign * for multiplication). Repeat steps 2 and 3 above for the new variable.

On your separate page please answer the following questions (worth 8 points):

6. Calculate the SS for each of the three main quantitative variables using the variance you obtained in SPSS (this should be on a sheet separate from the SPSS output). Note: Remember the relationship between variance and SS to help you do this.

7. Write 1-2 sentences (on your separate page) for each of the three main quantitative variables including the following: values of the mean, median, standard deviation and approximate shape of the distribution (look at the histogram). The shape may not be obvious; this is ok. Just do your best to describe what you think is going on with the data (e.g., mention whether you think there is skew, are there are any outliers, is it bimodal?).

8. Answer the following questions:
   1. What happened to the mean and standard deviation of sleeptwo compared to the original mean and standard deviation of that variable?
   2. What happened to the shape of the distribution of the sleep variable after multiplying by two (compared to the original variable)? What is the explanation for this?

Answer 1

Descriptive Statistics
	N	Minimum	Maximum	Sum	Mean	Std. Deviation	Variance
Sleep_duration	40	328.00	600.00	16993.00	424.8250	65.33813	4269.071
Valid N (listwise)	40

Descriptive Statistics
	N	Minimum	Maximum	Sum	Mean	Std. Deviation	Variance
Wins2	30	16.00	67.00	1306.00	43.5333	12.91279	166.740
Valid N (listwise)	30

Descriptive Statistics
	N	Minimum	Maximum	Sum	Mean	Std. Deviation	Variance
Words3	23	180.00	359.00	5952.00	258.7826	45.42522	2063.451
Valid N (listwise)	23

Descriptive statistics for all three quantitave variables are shown in first three tables.

Mean for sleep duration is highest i.e 424.8250

Variance of sleep duration is highest i.e. 4269.071