# What is Statistics?

*label*Mathematics

*timer*Asked: Dec 15th, 2018

*account_balance_wallet*$35

**Question description**

I have a quiz with 20 questions that need to be answered please help me with that. I need an A..

## Tutor Answer

I put the questions and answers in separate documents. Please let me know if you need something else.

STAT 200

OL4 / US2 Sections

Final Exam

Spring 2018

1. QUESTION 1

a) ITEM A.

True. The intersection of A and B, P(A AND B), consists of outcomes that are in both A and

B. The union of A and B, P(A OR B), consists of outcomes that are in A or B or both.

b) ITEM B.

False. The statistic variance only measures the dispersion of a data set from its mean value.

A variance with a value of 0 implies that all the values are equal to the mean but not

necessary, all data must be zero.

c) ITEM C.

False. The volume of milk can be fractional with a continuous and infinite number of

possibilities (quantitative continuous variable).

d) ITEM D.

True. The standard deviation is the statistic that show how spread are the values from the

mean. The more spread out a data distribution is, the greater its standard deviation.

e) ITEM E.

False. The P-value of this case is 0.03 and it’s lower than the level of significance, supporting

that there is enough evidence to reject the null hypothesis and accept the alternative

hypothesis.

2. QUESTION 2.

a) ITEM A. ANSWER:

(i) Statistic

A statistic is a numerical summary of a sample (100 students graduated from UMUC in

2016) taken from the population (students graduated from UMUC in 2016).

b) ITEM B. ANSWER

(iii) Ordinal

An ordinal scale classifies data into a rank of categories (from 0 to 5 stars).

c) ITEM C. ANSWER

(iii) Systematic

The systematic sampling is also called interval sampling, meaning that is an interval

between the units selected for the study.

3. QUESTION 3

a) ITEM A.

IQ Scores 50-69

25

𝐶𝑅𝐹 =

= 0.025

1000

IQ Scores 70-89

25

250

275

𝐶𝑅𝐹 =

+

=

= 0.275

1000 1000 1000

IQ Scores 90-109

25

250

𝑥

725

𝐶𝑅𝐹 =

+

+

=

= 0.725

1000 1000 1000 1000

𝑥 = 450

Total Frequency

𝑇𝐹 = 1000 = 25 + 250 + 450 + 𝑥 + 27

𝑥 = 248

IQ Scores 110-129

25

250

450

248

973

𝐶𝑅𝐹 =

+

+

+

=

= 0.973

1000 1000 1000 1000 1000

IQ Scores 130-149

25

250

450

248

27

1000

𝐶𝑅𝐹 =

+

+

+

+

=

= 1.000

1000 1000 1000 1000 1000 1000

b) ITEM B.

450

248

𝑃(%) = 𝑃90−119 + 𝑃120−139 = (

+

) × 100 = 69.8

1000 1000

c) ITEM C.

The median of this distribution is in the group with an IQ score between 90-109. The median

is the middle value of the observations when the observations are ordered from the smallest

to the largest. In this case, the group where the cumulative frequency of 0.500 is located.

4. QUESTION 4.

a) ITEM A.

The range is the difference between the largest and the smallest observations.

𝑅 = 100 − 15 = 85

b) ITEM B. ANSWER:

(iii) 45 – 65

This group of scores between 45 and 65 include the first and the second quartile, meaning

that there is at least 25% of the sample (50 students); also, includes the group of scores

between 45 and 55, a group in common with the score band of 35-55, making the comparison

between the bands of 35-45 and 55-65 for the options (ii) and (iii). The option (i) is discarded

because it doesn’t have a quartile, meaning that the number of students is less than 50

students.

c) ITEM C. ANSWER:

(iii) 50

Between 65 (second quartile) and 85 (third quartile) there is the 25% of the sample (50

students).

5. QUESTION 5.

a) ITEM A.

P(A) = The first selected card is an ace

P(B) = The second selected card is an ace

With replacement means that in the second event, the number total aces and cards will be the

same as the first event.

𝑃(𝐴 ∩ 𝐵) = 𝑃(𝐴) × 𝑃(𝐵) =

4

4

16

×

=

= 0.0059

52 52 2704

b) ITEM B.

Without replacement means that in the second event, the number total aces will be 3 and cards

will be 51.

𝑃(𝐴 ∩ 𝐵) = 𝑃(𝐴) × 𝑃(𝐵) =

4

3

12

×

=

= 0.0045

52 51 2652

6. QUESTION 6.

a) ITEM A

The event (S OR P) means the situation where the randomly selected student takes STAT200

or PSYC300.

b) ITEM B.

300

= 0.300

1000

150

𝑃(𝑃) =

= 0.150

1000

50

𝑃(𝑆 ∩ 𝑃) =

= 0.050

1000

𝑃(𝑆) =

𝑃(𝑆 ∪ 𝑃) = 𝑃(𝑆) + 𝑃(𝑃) − 𝑃(𝑆 ∩ 𝑃) =

300

150

50

400

+

−

=

= 0.400

1000 1000 1000 1000

7. QUESTION 7.

a) ITEM A.

There are three possibilities to have a sum of exactly 6 after two rolls: 2+4, 4+2, and 3+3.

3

𝑃(𝐴) =

= 0.083

36

There are three possibilities to have an even number when the dice is rolled first.

3

𝑃(𝐵) = = 0.500

6

If the first dice is an even number, the possibilities to have a sum of exactly 6, after two rolls,

reduced to two events: 2+4, and 4+2.

2

𝑃(𝐴 ∩ 𝐵) =

= 0.056

36

b) ITEM B.

No. The variables are dependent, the multiplication rule is not met.

𝑃(𝐴)𝑃(𝐵) = 0.083 × 0.50...

*flag*Report DMCA

Brown University

1271 Tutors

California Institute of Technology

2131 Tutors

Carnegie Mellon University

982 Tutors

Columbia University

1256 Tutors

Dartmouth University

2113 Tutors

Emory University

2279 Tutors

Harvard University

599 Tutors

Massachusetts Institute of Technology

2319 Tutors

New York University

1645 Tutors

Notre Dam University

1911 Tutors

Oklahoma University

2122 Tutors

Pennsylvania State University

932 Tutors

Princeton University

1211 Tutors

Stanford University

983 Tutors

University of California

1282 Tutors

Oxford University

123 Tutors

Yale University

2325 Tutors