Statistical Analysis

Statistical Analysis

Question 1

Identify each of the following as examples of nominal, ordinal, interval, or ratio scales of measurement.1. A poll of registered voters in Florida asking which candidate they support.

Nominal2. The length of time required for a wound to heal when using a new medicineInterval 3. The number of telephone calls arriving at a switchboard per five-minute periodRatio4. The distance first-year college football players can kick a ballInterval5. Mental health diagnoses present in an elderly populationNominal6. The rankings of employees on their job performanceOrdinal

Question 2

2) Two hundred raffle tickets are sold. Your friend has five people in her family who each bought two raffle tickets. What is the probability that someone from her family will win the raffle? Each of the 5 Family members bought 2 tickets, so total tickets = 10 tickets

Probability = 10/200 = 0.05 or 5%.

Question 4

3) Jolie has 45 minutes to do her statistics homework. If the mean is 38 minutes and the standard deviation is 3, calculate Jolie's z score. Once calculated, interpret your findings in terms of Jolie's performance.x= 45, µ = 38, s = 3

Z= (45-38)/ 3

Z= 2.33

The z-score of 2.33 explains that the obtained marks vary 2.33 times the standard deviation from mean.

Question 4

4) . A psychologist measures units of change for a memory test after students are given an opportunity to sleep only four hours. The following change units were obtained: 7, -12, 4, -7, 3, -10. Find the a) mean, b) median, c) mode, d) standard deviation, e) range, and f) variance.a)Mean = (7-12+4-7+3-10)/6

Mean = -2.5

b)For Median we will arrange the ungrouped data in ascending order

-12, -10, -7, 3, 4, 7

Here Median = (-7+3)/2

Median = -2

c)Mode, since these all the values don't have any value common therefore

Mode = NIL

d)Standard Deviation

X

X-Mean

SQR

7

9.5

90.25

-12

-9.5

90.25

4

6.5

42.25

-7

-4.5

20.25

3

5.5

30.25

-10

-7.5

56.25

Total

-2.5

329.5

SD = SQRT[329.5 / 6]

SD = 7.41

e) Range , Highest = 7 - (12) = -5

f)Variance = 54.91

Question 5

5) A student scored 81 on a chemistry test and 75 on a history test. For the chemistry test, the mean was 70 and the standard deviation was 20. For the history test, the mean was 65 and the standard deviation was 8. Did the student do better on the chemistry test or the history test? Explain your answer

We can make a comparison based on coefficient of variation (CV),

CV (Chemistry) = 70/20 = 3.5

CV (History) = 65/8 = 8.125

The student did better in the history as there is more variability ...