STA 2023   Practice TEST 1

 

1) A fitness club surveys 40 randomly selected members & finds the average

     weight of those questioned is 157 pounds. Is this value a parameter or a statistic? 

 

                                                                                                ________________________

 

2) Tell if the value is continuous or discrete.

    a)  number of stories in a building                                          ________________________

 

    b) height of a tree in feet                                                        ________________________

 

3) a) A marketing firm surveys 100 people to see how many use a certain product

         & 15 say they  do.

         Is this study observational or experimental?                      ________________________

 

    b) A professor gives one class a practice test and compares actual test grades

        to a class that does not get the practice test.

        Is this study observational or experimental?                       ________________________

 

4) Identify the BEST level of measurement for each: ratio, interval, ordinal

     or nominal.

   

    a) amount of fat in grams in cookies.                          ________________________

 

    b) subjects in which college students major                ________________________

 

For # 5 – 14, use this sample list of quiz scores & you may use your calculator to help in any way. Round answers to nearest tenth.

3          6          8          9          10        11        11        13        13        14        14        15       

15        15        16        16        16        17        18        20

 

.

5) Find the mean.                                                                      ________________________

 

6) Find the median.                                                                   ________________________

 

7) Find the mode(s), if any.                                                       ________________________

 

8) Find the range.                                                                     ________________________

 

9) a) Find Q1 .                                                                          ________________________

 

    b) Find Q3.                                                                           ________________________

 

10) Find the extremes.                                                              ________________________

 

11) Find the standard deviation                                     _______________________

 

12) Find the variance.                                                               _______________________

 

 

 

13) Find the z-score for data value 18.  (round to 2 places)       ______________________

 

 

 

 

14) Is the data value 18 unusual or not unusual?             _______________________

 

 

15) Use your calculator to make a box-plot and copy it here.

 

 

 

 

 

 

 


For #16 & 17, z is a STANDARD normal distribution.

16) Find the probability that z lies between ( –2.41) and 1.63.

(Round to 4 decimal places.)                                                     ________________________

 

 

 

17) Find the probability that z < 1.13   (Round to 4 places.)

                                                                                    ________________________

 

 

 

 

18) Scores on a test are normally distributed with a mean of 78.5 and standard deviation

     of 7.9. Find the score which is the 80th percentile. (round to the appropriate whole

     number.)

______________________

 

 

 

 

 

 

 

19) The time it takes a mechanic to re-build the transmission of a 1992 Chevy shows

      the mean is 8.4 hours and standard deviation is 1.8 hours.  If a mechanic is

      randomly chosen, find the probability that his re-build time exceeds 9.1 hours.

      (Round to 4 decimal places.)

 

 

 

 

 

 


20) According to the Empirical Rule, what percentage of values in a normal distribution

      will be within two standard deviations of the mean?

                                                                                          _________________________

 

 

21) 5000 students were surveyed to see what degree they are seeking and 

       the results are in this pie chart.

                                                   

                                                                                 

a)      What program has the most students?

 


b)      How many students are taking Personal Interest courses?

 

 

 

 

 


c)      How many degrees of the circle for A.A. degree?

 

 

 

 

22) Use this histogram that follows to answer the questions below.

 

a)      How many scored 17 to 20?

 

b)      What is the relative frequency for the class (category) 17 to 20?

 

 

 

c)      What is the class midpoint of the class (category) 17 to 20?

 

 

 

d)      Is this data more symmetric or skewed?