Question

1) Generate a data set with three variables (X, Y and Z). X and Y have 10 observations for each (N=10), and Z has 13 observations (N=13). Each observation should have two digits (such as “83” or “8.3”).

2) Draw a stem-and-leaf display for variable Z only and draw a box plot display for variable Z after specifying the 5 numbers (UEX, LEX, FU, FL, MD).

3) Calculate the mean and standard deviation for variable X

4) Calculate the mean and standard deviation for variable Y

5) In order to predict Y from X, we need to set up a regression equation: (a) Calculate two regression constants (slope and y-intercept) and (b) present the equation.

6) As you have the mean for variable X and Y (from questions 3 and 4 above), once you have the mean for variable Z, can you obtain the mean for the entire data set by computing the mean of the three means? Why or why not? Explain.

Answer 1

x	y
99	16
63	34
95	51
39	97
59	84
95	24
66	13
75	22
37	74
88	12

and

z
1.2
3.8
3.1
8.6
0.4
8.4
2.1
3.3
7.1
5.0
2.7
6.2
5.1

2. Stem leaf diagram for z :

STEM	LEAF
0	4
1	2
2	1 , 7
3	1 , 3 , 8
5	0 , 1
6	2
7	1
8	4 , 6

2.The box plot:

3. Mean of x is ;

  

= 716/10 = 71.60

standard deviation of x is :

  

  

= 21.56

4. Similarly mean of y is :

  

and standard deviation of y is :

  

= 30.15

If you want to know the procedures, let me know in the comment section.