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2 years ago

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Researchers for a company that manufactures batteries want to test the hypothesis that the mean battery life of their new batter

y is greater than the known mean battery life of their older version. The researchers selected random samples of 32 of the new batteries, subjected the batteries to continuous use, and determined the mean and standard deviation of the battery lives in the sample. Which of the following is an appropriate test for the researchers' hypothesis?
a. A one-sample z-test for a population mean.
b. A one-sample t-test for a population mean.
c. A one-sample z-test for a population proportion.
d. A matched-pairs t-test for a mean difference
e. A two-sample t-test for a difference between means

1 answer:

guapka [62]2 years ago

8 0

(b) one-sample t-test for a population mean

ur welcome :D

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A store buys frozen burritos from a supplier for $1.40 each. The store adds a markup of 80% to determine the retail price. This

boyakko [2]

$1.40 - price from a supplier = 100%
100% + 80% = 180% = 1,8 - the retail price

1,40 * 1,8 = $2,52 - the retail price

100% - 25% = 75% = 0,75 - on sale for 25% off

2,52 * 0,75 = $1,89 - the sale price.

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3 years ago

Jackson makes 7 calls each day after 36 days how many calls will Jackson make?

oksian1 [2.3K]

Answer:

352 calls

Step-by-step explanation:

Each day he makes 7 calls and 36 days have gone by so you'll multiply 36 and 7.

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2 years ago

Calculate the slope of a line that passes through the points (-4,7) and (-1,3)

zmey [24]

Answer:

The answer is

$- \frac{4}{3} \\$

Step-by-step explanation:

The slope of a line given two points can be found by using the formula

$m = \frac{ y_2 - y _ 1}{x_ 2 - x_ 1} \\$

where

(x1 , y1) and (x2 , y2) are the points

From the question the points are

(-4,7) and (-1,3)

We have

$m = \frac{3 - 7}{ - 1 - - 4} = \frac{ - 4}{ - 1 + 4} = - \frac{4}{3} \\$

We have the final answer as

$- \frac{4}{3} \\$

Hope this helps you

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3 years ago

An open box with a square base is constructed so that it has a volume of 64in^3. The base needs to be made out of a material tha

Ivahew [28]

The volume of a box is the amount of space in the box

The dimensions that minimize the cost of the box is 4 in by 4 in by 4 in

<h3>How to determine the dimensions that minimize the cost</h3>

The dimensions of the box are:

Width = x

Depth = y

So, the volume (V) is:

$V = x^2y$

The volume is given as 64 cubic inches.

So, we have:

$x^2y = 64$

Make y the subject

$y = \frac{64}{x^2}$

The surface area of the box is calculated as:

$A =x^2 + 4xy$

The cost is:

$C = 2x^2 + 4xy$ --- the base is twice as expensive as the sides

Substitute $y = \frac{64}{x^2}$

$C = 2x^2 + 4x * \frac{64}{x^2}$

$C =2x^2 + \frac{256}{x}$

Differentiate

$C' =4x - \frac{256}{x^2}$

Set to 0

$4x - \frac{256}{x^2} = 0$

Multiply through by x^2

$4x^3 - 256= 0$

Divide through by 4

$x^3 - 64= 0$

Add 64 to both sides

$x^3 = 64$

Take the cube roots of both sides

$x = 4$

Recall that:

$y = \frac{64}{x^2}$

So, we have:

$y = \frac{64}{4^2}$

$y = 4$

Hence, the dimensions that minimize the cost of the box is 4 in by 4 in by 4 in

Read more about volume at:

brainly.com/question/1972490

4 0

2 years ago

Need quick help with 2 math equations asap! Thanks!

solong [7]

Before answering, keep in mind that parallel lines have equal slopes and perpendicular lines have negative reciprocal slopes. Each problem has you find the slope and then use that rule.

For line F, $m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}}}$

Let x $x_{1}$ = 7, x $x_{2}$ = 9, y $y_{1}$ = 13, y $y_{2}$ = -3

$m = \frac{-3 - 13}{9-7}$

$m = \frac {-16}{2}$

m = 8

For line E, the calculations are similar and the slope is 3/5. The perpendicular line would have m = -5/3.

5 0

2 years ago