Topic Quiz Q.7: Measures of center and spread

Question 1 of 10 · Mean, median, mode, range, weighted average

Fill in

Keisha bowled four games with scores of 142, 165, 138, and 151. What score does she need in her fifth game so that her mean score for all five games is exactly 150?

Type your answer in the box. Fractions like 3/4 are fine.

Hint

A mean of 150 over 5 games means the five scores must add up to a certain total. What is that total?

Question 2 of 10 · Mean, median, mode, range, weighted average

In Ms. Patel's class, the final grade is a weighted average:

CategoryWeightAna's score
Tests40%85
Homework35%92
Final exam25%70

What is Ana's final grade?

Answer choices
Hint

Multiply each score by its weight (as a decimal), then add. The weights already add to 100%, so you do not divide by 3.

Question 3 of 10 · Mean, median, mode, range, weighted average

Fill in

A community center surveyed 30 families about how many children live in their home.

Number of children01234
Number of families691221

What is the mean number of children per family? Round to the nearest tenth.

children

Type your answer in the box. Fractions like 3/4 are fine.

Hint

Each row of the table stands for many families. Multiply to find the total number of children, then divide by the total number of families.

Question 4 of 10 · Mean, median, mode, range, weighted average

Fill in

The dot plot shows how many hours each member of a neighborhood cleanup club volunteered last month. Each dot is one member.

Dot plot of hours volunteered last month by 15 club members, each dot is one member: 1 hour 2 dots, 2 hours 3 dots, 3 hours 4 dots, 4 hours 3 dots, 5 hours 1 dot, 6 hours 0 dots, 7 hours 2 dots.1234567Hours volunteered last month (each dot = 1 member)

What is the median number of hours volunteered?

hours

Type your answer in the box. Fractions like 3/4 are fine.

Hint

Count the dots to find how many members there are. Then count from the left to the middle dot.

Question 5 of 10 · Mean, median, mode, range, weighted average

No calculator

A youth soccer team scored these numbers of goals in its first 10 games:

2, 0, 3, 1, 2, 4, 1, 0, 2, 1

Which statement about the mode of the data is true?

Answer choices
Hint

Make a tally: how many times does each number of goals appear? Can more than one value be the mode?

Question 6 of 10 · Mean, median, mode, range, weighted average

Fill in

A store sold T-shirts at three prices last month:

Price per shirtNumber sold
$1142
$1623
$2415

What was the mean price of all the shirts sold? Round to the nearest cent.

$

Type your answer in the box. Fractions like 3/4 are fine.

Hint

This is a weighted average: each price counts as many times as the number of shirts sold at that price.

Question 7 of 10 · Mean, median, mode, range, weighted average

Drop-down

Seven students in a GED class took a practice test. Their scores were:

88, 91, 85, 90, 42, 87, 89

The mean score is about 81.7.

Choose the correct answer for each blank.

The outlier in this data set is . The outlier makes the mean the median, so the better describes a typical score.

Choose an answer from each menu.

Hint

Find the value far from the others. Then sort the data to find the median and compare it with the mean of 81.7.

Question 8 of 10 · Mean, median, mode, range, weighted average

A hiking club has 40 members with a mean age of 31 years. The 25 women in the club have a mean age of 34 years. What is the mean age of the men in the club?

Answer choices
Hint

Work with totals: find the total age of all members and the total age of the women. How many men are there?

Question 9 of 10 · Mean, median, mode, range, weighted average

In a training course, the final grade is 60% test average and 40% homework average. Carlos has a homework average of 95. What is the lowest test average he can have and still earn a final grade of at least 80?

Answer choices
Hint

Write the weighted-average equation with the test average as the unknown, set it equal to 80, and solve.

Question 10 of 10 · Mean, median, mode, range, weighted average

Drag and drop

At a community college, a grade of A is worth 4.0 points and a grade of B is worth 3.0 points. A student's GPA is the mean of the grade points, weighted by credits.

CourseCreditsGrade
Biology4A
English3B
Math4B
Art1A

Drag the correct value into each box. Not every value is used.

Total grade pointsTotal creditsGPA (to the nearest hundredth)

Tap a tile, then tap a box to place it.

Hint

Each course's grade points are credits × grade value. The GPA divides the total grade points by the total credits, not by the number of courses.

Formula sheet

Area

Area of a square s = length of a side
A = s^2
Area of a rectangle l = length, w = width
A = lw
Area of a parallelogram b = base, h = height (straight up from the base, not the slanted side)
A = bh
Area of a triangle b = base, h = height
A = \tfrac{1}{2}bh
Area of a trapezoid b_1 and b_2 = the two parallel sides, h = height
A = \tfrac{1}{2}h(b_1 + b_2)
Area of a circle r = radius (half of the diameter); \pi \approx 3.14
A = \pi r^2

Perimeter and circumference

Perimeter of a square s = length of a side
P = 4s
Perimeter of a rectangle l = length, w = width
P = 2l + 2w
Perimeter of a triangle s_1, s_2, s_3 = the three side lengths
P = s_1 + s_2 + s_3
Circumference of a circle the distance around a circle; r = radius, d = diameter, \pi \approx 3.14
C = 2\pi r = \pi d

Surface area (SA) and volume (V)

p = perimeter of the base with area B; \pi \approx 3.14

Rectangular prism l = length, w = width, h = height
SA = 2lw + 2lh + 2wh \qquad V = lwh
Right prism B = area of the base, p = perimeter of the base, h = height
SA = ph + 2B \qquad V = Bh
Cylinder r = radius of the base, h = height
SA = 2\pi rh + 2\pi r^2 \qquad V = \pi r^2 h
Pyramid B = area of the base, p = perimeter of the base, s = slant height, h = height
SA = \tfrac{1}{2}ps + B \qquad V = \tfrac{1}{3}Bh
Cone r = radius of the base, s = slant height, h = height
SA = \pi rs + \pi r^2 \qquad V = \tfrac{1}{3}\pi r^2 h
Sphere r = radius
SA = 4\pi r^2 \qquad V = \tfrac{4}{3}\pi r^3

Data

Mean (average) add all the values of the data set, then divide by how many values there are
\text{mean} = \dfrac{\text{total of the values}}{\text{number of values}}
Median
the middle value when the data are in order; with an even number of values, it is the mean of the two middle values

Algebra

Slope of a line (x_1, y_1) and (x_2, y_2) = two points on the line
m = \dfrac{y_2 - y_1}{x_2 - x_1}
Slope-intercept form of a line m = slope, b = y-intercept (where the line crosses the y-axis)
y = mx + b
Point-slope form of a line m = slope, (x_1, y_1) = a point on the line
y - y_1 = m(x - x_1)
Standard form of a quadratic equation a, b, c are numbers and a \ne 0
y = ax^2 + bx + c
Quadratic formula solves ax^2 + bx + c = 0
x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}
Pythagorean theorem in a right triangle: a, b = the two legs, c = the hypotenuse (the longest side, across from the right angle)
a^2 + b^2 = c^2
Simple interest I = interest, P = principal (the amount saved or borrowed), r = rate per year as a decimal, t = time in years
I = Prt
Distance = rate × time d = distance, r = rate (speed), t = time
d = rt
Total cost
\text{total cost} = (\text{number of units}) \times (\text{price per unit})