Week 1 | Complete Solution

1.    In the graph, there are two distributions: A and B. 
  
We can know from the graph: 

a. Distribution A has a bigger standard deviation than distribution B 
b. Distribution B has a bigger standard deviation than distribution A 
c. Distribution A and distribution B have the same standard deviation 
d. We cannot tell which has a larger standard deviation from the graph 

2.    A researcher collected BMI (Body Mass Index) of 50 students in an Engineering school. He found the mean BMI was much smaller than the median BMI. The reason for this might be___ 

a. Several students had much smaller BMI scores than the other students 
b. Several students had much larger BMI scores than the rest 
c. The researcher made some measurement errors 
d. All the students had smaller BMI scores, compared to national average 

3.    What is the level of measure for each of the following:

a)    Final grades in this class                 _____________________

b)    Weights of newborn babies            _____________________

c)    Seasons of the year                _____________________

d)    Boiling temperatures of different liquids        _____________________

4.    Determine type of sampling used:

a)    I collected shoe sizes from my family        _____________________

b)    1003 adults were called after their phone 
numbers were randomly generated by computer   ____________________

c)    Police stopped every sixth driver for sobriety test ____________________

d)    U.S.D.O.C. collected data by randomly selecting
8    Federal prisons and surveying every prisoner       _____________________

 
5.    I collected radon samples from basements in my neighborhood and obtained the following:

Radon in cPi    Frequency
2-5    2
6-9    2
10-13    6
14-17    15
    
Identify class width                        ______________________
Identify class midpoints                    ______________________
Identify class boundaries                    ______________________
Create a histogram for these data.

 
6.    Create a scatterplot of car weights and braking distance using the data below. Based on the result, does there appear to be a relationship between weight of a car and its braking distance?

Weight (lb)    4035    3115    4115    3650    3565    4030
Braking Distance (ft)    131    136    129    127    146    146

 
7.    The weekly salaries for teachers of the different grades at my school are as follows:

Kindergarten    First    Second    Third    Fourth    Fifth
774    649    1210    546    431    612

Calculate the standard deviation. Do the different grades have much variation in salary?

8.    A simple random sample of pages of my dictionary was collected.  These are the number of words defined on each page. Find the mean, median, mode, and midrange.
51     63     36     43     34     62     73     39     53     79

There are 1459 pages. Estimate the total number of words in the dictionary. Is the estimate likely to be an accurate estimate of the total number of words in the English language?

9.    I had 10 students last term who earned the following grades:
 
98   85   89   73   76   85   87   92   85   56
    Find the first quartile:    ________________
    Find the median:    ________________
    Find the third quartile:________________
    Find the interquartile:_________________