2) Using the linear function, predict the number of soft-drink sales if the

9.4 The heights of a random sample of 50 college stu- dents showed a mean of 174.5 centimeters and a stan- dard deviation of 6.9

gladu [14]

Answer: a) (176.76,172.24), b) 0.976.

Step-by-step explanation:

Since we have given that

Mean height = 174.5 cm

Standard deviation = 6.9 cm

n = 50

we need to find the 98% confidence interval.

So, z = 2.326

(a) Construct a 98% confidence interval for the mean height of all college students.

$x\pm z\times \dfrac{\sigma}{\sqrt{n}}\\\\=(174.5\pm 2.326\times \dfrac{6.9}{\sqrt{50}})\\\\=(174.5+2.26,174.5-2.26)\\\\=(176.76,172.24)$

(b) What can we assert with 98% confidence about the possible size of our error if we estimate the mean height of all college students to be 174.5 centime- ters?

Error would be

$\dfrac{\sigma}{\sqrt{n}}\\\\=\dfrac{6.9}{\sqrt{50}}\\\\=0.976$

Hence, a) (176.76,172.24), b) 0.976.

8 0

3 years ago

Which of the points listed is the same distance from the x-axis as the point (8, 3.25)?

Akimi4 [234]

The distance of the point (8, 3.25) to the x-axis (the horizontal line) is 3.25.
incorrect - A.) is 4.75 away from the x-axis
This one is correct - B.) is 3.25 away from the x-axis
incorrect - C.) is 7 away from the x-axis
incorrect - D.) Actually one of the above answers it correct

Hope this helps

7 0

3 years ago

A fitted multiple regression equation is Y = 28 + 5X1 - 4X2 + 7X3 + 2X4. When X1 increases 2 units and X2 increases 2 units as w

ad-work [718]

Answer:

A. Increase by 2

Step-by-step explanation:

Given that a fitted multiple regression equation is

$Y = 28 + 5X_1 -4X_2 + 7X_3 + 2X_4$

This is a multiple regression line with dependent variable y and independent variables x1, x2, x3 and x4

The coefficients of independent variables represent the slope.

In other words the coefficients represent the rate of change of y when xi is changed by 1 unit.

Given that x3 and x4 remain unchanged and x1 increases by 2 and x2 by 2 units

Since slope of x1 is 5, we find for one unit change in x1 we can have 5 units change in y

i.e. for 2 units change in x1, we expect 10 units change in Y

Similarly for 2 units change in x2, we expect -2(4) units change in Y

Put together we have

$10-8 =2$ change in y

Since positive 2, there is an increase by 2

A. Increase by 2

5 0

3 years ago

The area of a rectangle is 63 m2 , and the length of the rectangle is 5 m more than double the width. find the dimensions of the

Kamila [148]

If you let x represent the width of the rectangle, then you can write the equation for area as
.. x(2x +5) -63 = 0
This has positive solution x=4.5.

The rectangle is 4.5 meters by 14 meters.

7 0

3 years ago

Isabella spends $4.87 on paintbrushes and paint. How many of each item does she buy? Explain how you found your answer. Paint br

Lelechka [254]

The complete question in the attached figure

Let
x-----------------> number of paintbrushes----------- > $0.95 each
y---------------- > number of jar of paint-------------- > $0.99 each

we know that
0.95x+0.99y = $4.87

using a graph tool

the solution will be a pair of coordinates that are whole numbers -- > see the attached figure

the solution is the point (2,3)

x=2---------------------- > number of paintbrushes
y=3---------------------- > number of jar of paint

the answer is
number of paintbrushes=2
number of jar of paint=3

8 0

3 years ago