Question

- The following data represents the exam scores of students in Econ 220 VV22, which is one of several sections of Econ 220 in a college. You can take this as a sample.

Student |
Score |

1 |
82 |

2 |
70 |

3 |
50 |

4 |
60 |

5 |
75 |

6 |
65 |

7 |
55 |

8 |
80 |

9 |
85 |

10 |
90 |

11 |
95 |

12 |
94 |

13 |
35 |

14 |
40 |

15 |
65 |

16 |
95 |

17 |
91 |

18 |
55 |

19 |
65 |

20 |
76 |

21 |
86 |

22 |
96 |

23 |
84 |

24 |
57 |

25 |
77 |

26 |
87 |

27 |
90 |

28 |
68 |

29 |
88 |

30 |
89 |

31 |
90 |

32 |
92 |

- Compute the standard deviation (you may use excel)

- Construct a 95% confidence interval.
- What is the probability that a randomly selected student scores more than 90.
- What is the probability that a randomly selected student scores less 90.
- What is the probability that a randomly selected student scores between 30 and 95?

Answer #1

Using excel you will find that for the sample

for 95% confidence interval

Z= 1.96

Therefore the 95% confidence interval is
**(69.99,81.69)**

**b)**

**P(X>90) = 1- P(X<=90)**

**c)**

d)

Below represent scores on an exam, each entry one score for one
student
40
99
59
98
63
63
64
65
67
35
67
67
68
70
71
71
71
46
72
72
60
73
74
74
74
75
97
75
62
76
76
76
76
76
77
57
77
98
77
63
78
78
78
79
79
80
80
80
80
80
81
81
92
81
93
82
82
83
83
83
83
83
83
83
84
84
84...

Using the accompanying Student Grades data, construct a scatter
chart for midterm versus final exam grades and add a linear
trendline. What is the model? If a student scores 7878 on the
midterm, what would you predict her grade on the final exam to
be?
Student
Midterm
Final Exam
1
75
64
2
85
91
3
80
68
4
88
83
5
76
60
6
67
80
7
78
74
8
95
94
9
67
61
10
93
87
11...

Below are the final exam scores of 25 introductory statistics
students.
42, 53, 63, 76, 76, 78, 80, 85, 86, 86, 87, 87, 88, 88, 89, 89, 90,
91, 92, 94, 95, 95, 96, 96, 97
Create a box plot of the distribution of these scores.Please
indicate the values the boundaries and the middle line of the box
represent respectively, use the 1.5 IQR rule to identify outlier(s)
if any, and show how you determine the values the two whiskers...

The Test Scores for a Statistics course are given in the Excel
below.
The data (X1, X2, X3, X4) are for each student.
X1 = score on exam #1
X2 = score on exam #2
X3 = score on exam #3
X4 = score on final exam
Your professor wants to know if all tests are created equal.
What is the F-Stat?
EXAM1
EXAM2
EXAM3
FINAL
73
80
75
65.86667
93
88
93
80.16667
89
91
90
78
96
98...

Since we are attempting to examine the behavior of a class of
students, the behavior of an individual (as we calculated in
objective 1) is really of little concern to us. Assuming that there
are 30 students enrolled for a typical class, use the central limit
theorem to calculate the following:
• What would be the shape of the
distribution of the average class grade of these 30 students?
• What would be the average class
average of...

Student Grades
Student
Test
Grade
1
76
62
2
84
90
3
79
68
4
88
84
5
76
58
6
66
79
7
75
73
8
94
93
9
66
65
10
92
86
11
80
53
12
87
83
13
86
49
14
63
72
15
92
87
16
75
89
17
69
81
18
92
94
19
79
78
20
60
71
21
68
84
22
71
74
23
61
74
24
68
54
25
76
97...

The following scores on the midterm exam in a math
class were recorded. Find IQR. 93 81 59 69 82 73 61 77 95 84 88 71
85 97 63 72 89 80 60 98 91 62 78 83 76 81 94 66 83 96

DHL recently selected a random sample of packages and weigh
them. The weights for the samples are given below.
Use Excel to develop a frequency distribution using classes
having equal widths.
Use Excel to develop a relative frequency and a cumulative
relative frequency distribution for the weights using the same
classes created in part b.
What percent of the sampled crates have weights greater than 96
pounds?
DHL
89
91
86
93
94
91
95
83
84
92
80
88...

As part of its freshman orientation process, a college gives a
math placement exam to incoming freshmen. The math department is
interested in whether there is a statistically significant
difference in the average exam score for students in different
programs, at a level of α=0.01 . The exam scores for random samples
of science, engineering, humanities, and business majors are shown
in the following table. The math department has confirmed that the
samples were randomly selected and independent, that the...

Make a relative frequency histogram using 6 classes; between
what two values could you expect to find 88.9% of the data,
according to Chebyshev.
Sample scores: 84, 67,80, 74, 81, 91, 95, 85, 82, 99, 77, 78,
88, 94, 82, 95, 71, 77, 91, 88, 96, 85, 70, 82, 88, 75, 90, 85, 89,
95, 85, 65, 86, 91

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