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TEA [102]
3 years ago
6

Help me with this problem please please:):)

Mathematics
1 answer:
Lady_Fox [76]3 years ago
6 0
I believe it is 12.5 :)
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A laptop producing company also produces laptop batteries, and claims that the batteries
gregori [183]

Answer:

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours. (P-value = 0).

The null and alternative hypothesis are:

H_0: \mu=4\\\\H_a:\mu< 4

Step-by-step explanation:

<em>The question is incomplete: To test this claim a sample or population standard deviation is needed.</em>

<em>We will estimate that the sample standard deviation is 2 hours, and use a t-test to test that claim.</em>

<em> NOTE (after solving): The difference between the sample mean and the mean of the null hypothesis is big enough to reject the null hypothesis, even when we have a sample standard deviation of 3.5 hours, which can be considered bigger than the maximum standard deviation for the sample.</em>

This is a hypothesis test for the population mean.

The claim is that the batteries power the laptops for significantly less than 4 hours.

Then, the null and alternative hypothesis are:

H_0: \mu=4\\\\H_a:\mu< 4

The significance level is 0.05.

The sample has a size n=500.

The sample mean is M=3.5.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=2.

The estimated standard error of the mean is computed using the formula:

s_M=\dfrac{s}{\sqrt{n}}=\dfrac{2}{\sqrt{500}}=0.0894

Then, we can calculate the t-statistic as:

t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{3.5-4}{0.0894}=\dfrac{-0.5}{0.0894}=-5.5902

The degrees of freedom for this sample size are:

df=n-1=500-1=499

This test is a left-tailed test, with 499 degrees of freedom and t=-5.5902, so the P-value for this test is calculated as (using a t-table):

P-value=P(t

As the P-value (0) is smaller than the significance level (0.05), the effect is  significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours.

5 0
3 years ago
What is the slope of a line that is parallel to the x-axis? m=
Ludmilka [50]
Parallel to the x-axis and perpendicular to the y-axis: zero
Parallel to the y-axis and perpendicular to the x-axis: undefined
I hope that's right, that's how I remember it
6 0
3 years ago
How do I simplify this?
WINSTONCH [101]

Answer:

sorry ... good luck tho.....

6 0
2 years ago
arjun is as twice as older than shriya. five years ago his age was three times shreya's age. find their present age.​
chubhunter [2.5K]

Answer:10 and 20

Step-by-step explanation:Shreyas age:X

Arjuns age: 2x

Shreyas age 5 years ago:x-5

Arjuns age 5 years ago: 2x-5

We get the equation: 2x-5=3(x-5)

2x-5=3x-15

2x-3x=-15+5

-x=-10

X= 10

Shreyas present age is 10 years

Arjuns present age is 2x(2×10) =20 years

Please mark my answer as Brainliest ❤️

7 0
3 years ago
Which term is used to describe how light is reflected from a minerals surface
pantera1 [17]

Answer:

Luster describes the reflection of light off a mineral's surface. Mineralogists have special terms to describe luster. Minerals that are opaque and shiny, such as pyrite, have a metallic luster.

Step-by-step explanation:

5 0
3 years ago
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