Hypothesis Testing
1) Suppose the length of gold chains has a population that is normally distributed with
a standard deviation of 5. You are walking down the street and sample 9 gold chains from
this population and obtain a mean length of 28.95 and a standard deviation of 6.3802.
Using an alpha value of ∝= 0.01, is this observed mean significantly different than an
expected jewelry of 27?
2) Suppose the size of drumsticks has a population that is normally distributed with a
standard deviation of 5. For your first-year project, you sample 36 drumsticks from this
population and obtain a mean size of 66.09 and a standard deviation of 4.6836.
Using an alpha value of ∝ = 0.01, is this observed mean significantly different than the
expected price of 67?
Measures of Central Tendency
1) The table below shows the wages earned by workers in a factory:
Amount earned Number of Workers
$25 2
$42 5
$91 8
$54 6
$46 9
Determine:
a) the mean,
b) median
c) and the mode from the above.
Question 2:
Question 3:
Pearson’s Moment Correlation Coefficient:
Part a)
X Y
141 95
242 84
123 79
200 87
158 79
143 82
Examine the table above and then calculate:
a) the Correlation Coefficient.
b) the coefficient of determination
Part b)
Age Income ($)
20 1500
30 3000
40 5000
50 7500
Examine the table above and then calculate:
a) the Correlation Coefficient.
b) the coefficient of determination
Binomial Distribution:
Question 1
b)The probability that no sixes are shown.
Question 2
The probability that at least one computer is available at any one time in an internet café is
0.75.
a) Mr. Word has made 16 visits to the café. Calculate the probability that on entry at
least one computer is available on exactly 10 occasions.
b) Ms. White makes 30 visits to the café, determine the probability that on entry at
least one computer is available on 20 or more occasions.
Confidence Intervals:
a) A novel had more than 250 pages and a random sample of 12 pages of the novel
was taken, and the number of words on each page counted. The mean number of
words for the sample was 124 words. and the standard deviation was 15.4 words.
Calculate (correct to the nearest whole number) 80% confidence limits for the mean
number of words for the pages of the entire novel.
b) Many people completed a quiz with ten questions. A sample of results for 30 of
those people was then randomly selected as shown in the following frequency table:
Probability:
1) Complete the table below and answer the questions that follow:
Blue Eyes Brown eyes Total
Eagle 25 42
Ravens 36 48
Total 56
a) What’s the population of birds in the survey?
b) What’s the probability that a bird selected at random is an eagle?
c) What’s the probability that a bird is a raven given that it has blue eyes?
d) What’s the probability that the bird is an eagle or has brown eyes?
2) From the information above, in an appropriate way, complete the following tree
diagram:
BL
Eagles
BR
BL
Ravens
BR
