Project #44328 - Statistics


Statistics: Please keep in a word document and show all workings.

1. Define each of the following terms:

a. Population    b. Dependent      c. variable d.Sample e. Constant f. Data g. Statistic

h. Variable i. Parameter j. Independent k. variable


2. What are four methods of acquiring knowledge? Write a short paragraph describing the essential characteristics of each.


3. Write a short paragraph comparing naturalistic observation and true experiments.


4. Distinguish between descriptive and inferential statistics. Use examples to illustrate the points you make.


5. Indicate which of the following situations involve descriptive statistics and which involve inferential statistics:

a. An annual stockholders’ report details the assets of the corporation.

b. A history instructor tells his class the number of students who received an A on a recent exam.

c. The mean of a sample set of scores is calculated to characterize the sample.

d. The sample data from a poll are used to estimate the opinion of the population.

e. A correlational study is conducted on a sample to determine whether educational level and income in the population are related.

f. A newspaper article reports the average salaries of federal employees from data collected on all federal employees.


6. For each of the following, identify the sample and population scores:

a. A social psychologist interested in drinking behavior investigates the number of drinks served in bars in a particular city on a Friday during “happy hour.” In the city, there are 213 bars. There are too many bars to monitor all of them, so she selects 20 and records the number of drinks served in them.

The following are the data:


50       82      47      65

40       76      61      72

35       43      65      76

63       66      83      82

57       72      71      58


7. To make a profit from a restaurant that specializes in low-cost quarter-pound hamburgers, it is necessary that each hamburger served weigh very close to 0.25 pound. Accordingly, the manager of the restaurant is interested in the variability among the weights of the hamburgers served each day. On a particular day, there are 450 hamburgers served. It would take too much time to weigh all 450, so the manager decides instead to weigh just 15. The following weights in pounds were obtained:



0.25       0.27        0.25

0.26       0.35        0.27

0.22       0.32        0.38

0.29       0.22        0.28

0.27       0.40        0.31


c. A machine that cuts steel blanks (used for making bolts) to their proper length is suspected of being unreliable. The shop supervisor decides to check the output of the machine. On the day of checking, the machine is set to produce 2-centimeter blanks. The acceptable tolerance is ±0.05 centimeter. It would take too much time to measure all 600 blanks produced in 1 day, so a representative group of 25 is selected. The following lengths in centimeters were obtained:



2.01     1.99    2.05    1.94    2.05

2.01     2.02    2.04    1.93    1.95

2.03     1.97    2.00    1.98    1.96

2.05     1.96    2.00    2.01    1.99

1.98     1.95    1.97    2.04    2.02



d. A physiological psychologist, working at Tacoma University, is interested in the resting, diastolic heart rates of all the female students attending the university. She randomly samples 30 females from the student body and records the following diastolic heart rates while the students are lying on a cot. Scores are in beats/min.

62    85   92   85   88    71

73    82   84   89   93    75

81    72   97   78   90    87

78    74   61   66   83    68

67    83   75   70   86   72     


8. Identify which of the following represent continuous variables and which are discrete variables:

a. Time of day

b. Number of females in your class

c. Number of bar presses by a rat in a Skinner box

d. Age of subjects in an experiment

e. Number of words remembered

f. Weight of food eaten

g. Percentage of students in your class who are females

h. Speed of runners in a race

9. Identify the scaling of each of the following variables:

a. Number of bicycles ridden by students in the freshman class

b. Types of bicycles ridden by students in the freshman class

c. The IQ of your teachers (assume equal interval scaling)

d. Proficiency in mathematics, graded in the categories of poor, fair, and good

e. Anxiety over public speaking, scored on a scale of 0–100 (Assume the difference in anxiety between adjacent units throughout the scale is not the same.)

f. The weight of a group of dieters

g. The time it takes to react to the sound of a tone

h. Proficiency in mathematics, scored on a scale of 0–100 (The scale is well standardized and can be thought of as having equal intervals between adjacent units.)

i. Ratings of professors by students on a 50-point scale (There is an insufficient basis for assuming equal intervals between adjacent units.)


10. A student is measuring assertiveness with an interval scale. Is it correct to say that a score of 30 on the scale represents half as much assertiveness as a score of 60? Explain.


11. Find the values of the expressions listed here:

a. Find a 4  Xi for the scores X1 =3, X2= 5, X3 =7, X4 =10.



b. Find a 6 Xi for the scores X1 =2, X2 =3, X3 = 4, X4 = 6, X5 = 9, X6 =11, X7 = 14.



c. Find a NXi for the scores X1 =10, X2 = 12, X3 =13, X4 =15, X5 =18.



d. Find a N-1 Xi for the scores X1 = 22, X2 = 24, X3 =28, X4 = 35, X5 = 38, X6 =40.




12. Represent each of the following with summation

notation. Assume the total number of scores is 10.

a. X1 + X2 +X3 + X4+ +X10

b. X1 +X2 + X3

c. X2 + X3 + X4

d. X22 + X32 + X42 + X52


Subject Mathematics
Due By (Pacific Time) 10/21/2014 09:00 pm
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