EASY

ANSWER . C

Express by using the summation notation

Answer:

Find the percentile P25

for the distribution.

Answer: 10.55 tons

Table 3.8 shows the distribution of the maximum loads in short tons ( 1 short ton = 2000 lb) supported by

certain cables produced by a company.

Express by using the summation notation.

Answer:

Express by using the summation notation

Answer

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the lower limit of the eighth class.

Answer 1000

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the upper limit of the fifth class.

Answer 799

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the class boundaries of the last class.

Answer 1099.5

and 1199.5

On a final examination in mathematics, the mean was 72 and

the standard deviation was 15. Determine the standard scores (i.e.,

grades in standard-deviation units) of students receiving the grades of 72.

A ball is drawn at random from a box containing 6 red balls, 4 white balls, and 5 blue balls. Determine the probability that the ball drawn is white.

Solution

ANS. a

Table 2.5. Frequency distribution of the weekly wages of 65 employees at the P & R Company.

With reference to this table, determine the class interval having the largest frequency. This is sometimes called the modal class interval; Its frequency is then called the modal class frequency.

Answer: $270.00 – $279.99

ANS. B

Table 2.5. Frequency distribution of the weekly wages of 65 employees at the P & R Company.

With reference to this table, determine the lower limit of the sixth class.

Answer$300

ANS. b

Table 2.5. Frequency distribution of the weekly wages of 65 employees at the P & R Company.

With reference to this table, determine the class mark ( or class midpoint) of the third class.

Answer$274.995 or $275.00

AVERAGE

A ball is drawn at random from a box containing 6 red balls, 4 white balls, and 5 blue balls.

Determine the probability that the ball drawn is red.

Solution

Find the quadratic mean of the numbers 3, 5, 6,

6, 7, 10, and 12.

Find the quartile Q3 for

the distribution.

Answer: 11.57 tons

Table 3.8 shows the distribution of the maximum loads in short tons ( 1 short ton = 2000 lb) supported by

certain cables produced by a company.

Out of 100 numbers, 20 were 4’s, 40 were 5’s, 30 were 6’s and the remainder were 7’s. Find the arithmetic mean of the number.

Solution

A car travels 25 miles at 25 miles per hour (mph), 25

miles at 50 mph, and 25 miles at 75 mph. Find the harmonic

of the three velocities.Solution

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the percentage of students whose viewing times are at least 500 minutes but less than 1000 minutes.

Answer78.0%

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the percentage of the students with viewing times greater than or equal to 900 minutes.

Answer19.0%

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the percentage of students whose weekly viewing time does not exceed 600 minutes.

Answer 29.5%

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the class mark of the seventh class.

Answer 949.5

Table 2.14. Frequency distribution for the number of minutes per week spent watching TV by 400 Junior High Students.

With reference to this table determine the relative frequency of the sixth class.

Answer 15.5%

A ball is drawn at random from a box containing 6 red balls, 4 white balls, and 5 blue balls.

Determine the probability that the ball drawn is not red.

Solution

A ball is drawn at random from a box containing 6 red

balls, 4 white balls, and 5 blue balls. Determine the probability that the ball

drawn is blue.Solution

On a final examination in mathematics, the mean was 72

and the standard deviation was 15. Determine the standard scores

(i.e., grades in standard-deviation units) of students receiving the

grades of 60.

Solution

A ball is drawn at random from a box containing 6 red

balls, 4 white balls, and 5 blue balls. Determine the probability that the ball drawn is red or white.

Solution

One bag contains 4 white balls and 2 black balls; another

contains 3 white balls and 5 black balls. If one ball is drawn

from each bag, find the probability that both are white.

Solution

DIFFICULT

In a company having 80 employees, 60 earn $10.00

per hour and 20 earn $13.00 per hour. Determine the mean earnings per hour.

One bag contains 4 white balls and 2 black balls; another

contains 3 white balls and 5 black balls. If one ball is drawn

from each bag, find the probability that both are black.

Solution

One bag contains 4 white balls and 2 black balls; another contains 3

white balls and 5 black balls. If one ball is drawn from each bag, find the probability that one is white

and one is black.Solution

In a given business venture a lady can make a profit of

$300 with probability of 0.6 or take a loss of $100 with

probability of 0.4. Determine her expectation.

Solution

Four different mathematics books, 6 different physics books, and 2

different chemistry books are to be arranged on a shelf. How many

different arrangements are possible if the books in each particular

subject must all stand together?Solution

Out of 5 mathematicians and 7 physicists, a committee consisting

of 2 mathematicians and 3 physicists is to be formed. In how many ways can this be done if any mathematician and any physicist

can be included?Solution

Out of 5 mathematicians and 7 physicists, a committee consisting

of 2 mathematicians and 3 physicists is to be formed. In how many ways can this be done if one particular physicist must be on the

committee?

Out of 5 mathematicians and 7 physicists, a committee consisting

of 2 mathematicians and 3 physicists is to be formed. In how many ways can this be done if two particular mathematicians cannot

be on the committee?Solutionn

A factory finds that, on average, 20% of the bolts produced by a given

machine will be defective for certain specified requirements. If 10 bolts are selected at random from the day’s production of this machine, find the probability that exactly 2

will be defective.

On a final examination in mathematics, the mean was 72 and

the standard deviation was 15. Determine the standard scores (i.e.,

grades in standard-deviation units) of students receiving the grades of 93.

Find the coefficient of linear correlation between the variables X

and Y presented in Table 14.7.

Solution

Table 17.25 shows how 10 students, arranged in alphabetical order, were rank according to their achievements in both the laboratory and lecture sections of a biology course. Find the coefficient of rank correlation.