How much more is 3/8 gallon than 1/4 gallon?

Test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, and then state the concl

never [62]

Answer:

a) Failed to reject the null hypothesis (P-value=0.09).

b) The 95% CI for the difference in proportions is:

$-0.0599\leq\pi_1-\pi_2\leq0.0124$

Step-by-step explanation:

a) We have to perform a hypothesis test for the difference of proportions.

The null and alternative hypothesis are:

$H_0: \pi_1\geq\pi_2\\\\H_1: \pi_1$

The significance level is 0.05.

The proportion of the passenger cars owners is:

$p_1=\frac{239}{2142} =0.1116$

The proportion of commercial truck owners is:

$p_2=\frac{54}{399}=0.1353$

The weigthed average p is

$p=\frac{n_1p_1+n_2p_2}{n_1+n_2}=\frac{239+54}{2142+399}=0.1153$

The estimated standard deviation is

$s=\sqrt{\frac{p(1-p)}{n_1}+\frac{p(1-p)}{n_2}} =\sqrt{\frac{0.1153(1-0.1153)}{2142}+\frac{0.1153(1-0.1153)}{399}} =0.0174$

We can calculate the z-value as:

$z=\frac{\Delta p}{s}=\frac{0.1116-0.1353}{0.0174}=-1.362$

The P-value for z=-1.362 is P=0.0866.

The P-value (0.09) is greater than the significance level (0.05), so it failed to reject the null hypothesis. There is no enough evidence to prove that commercial trucks owners violate laws requiring front license plates at a higher rate than owners of passenger cars.

b) We can construct a 95% CI, according to the significance level of 0.05.

The z-value for this CI is 1.96.

We have to recalculate the standard deviation:

$\sigma=\sqrt{\frac{p_1(1-p_1)}{n_1} +\frac{p_2(1-p_2)}{n_2}} =\sqrt{\frac{0.1116(1-0.1116)}{2142} +\frac{0.1353(1-0.1353)}{399}} =0.0184$

The lower limit is then:

$LL=(p_1-p_2)-z*\sigma=(0.1116-0.1353)-1.96*0.0184=-0.0238-0.0361\\\\LL=-0.0599$

The upper limit is:

$UL=(p_1-p_2)+z*\sigma=(0.1116-0.1353)+1.96*0.0184=-0.0238+0.0361\\\\UL=0.0124$

The 95% CI for the difference in proportions is:

$-0.0599\leq\pi_1-\pi_2\leq0.0124$

In this case, we can conclude that the difference between the proportions, with 95% confidence, can still be equal or greater than zero, meaning that it is possible passenger car owners violate laws more than truck owners.

7 0

2 years ago

The cost of 8 kg of butter is $ 904. what will be the cost of 14 kg of butter

kvv77 [185]

Answer:

$1582

Step-by-step explanation:

cost of each kg 904/8=113

cost of 14 kg 113x14=1582

the cost of 14 kg of butter is $1582

6 0

2 years ago

A 2.2 GB game is being downloaded on your laptop. When you have downloaded half a gigabyte, you notice that your computer has be

zhannawk [14.2K]

In this question, you already download 0.5 GB of the total 2.2GB data you need which mean you only need to download 1.7GB left. If the speed of download is 0.01 GB per minute, then the time needed would be:
(2.2GB- 1.7GB) / (00.1GB/minute)= 1.5GB/ (0.01GB/minute)= 150 minute = 2.5 hours

Two hours would not be sufficient to download the data as you need 2.5 hours

3 0

2 years ago

A math teacher tells her students that eating a healthy breakfast on a test day will help their brain function and perform well

kogti [31]

Answer:

Step-by-step explanation:

Hello!

To test the claim that eating a healthy breakfast improves the performance of students on their test a math teacher randomly asked 46 students what did they have for breakfast before they took the final exam and classified them as:

<u>Group 1</u>: Ate healthy breakfast

X₁: Number of students that ate a healthy breakfast before the exam and earned 80% or higher.

n₁= 26

<u>Group 2: </u>Did not eat healthy breakfast

X₂: Number of students that did not eat a healthy breakfast before the exam and earned 80% or higher.

n₂= 20

After the test she counted the number of students that got 80% or more in the test for each group obtaining the following sample proportions:

p'₁= 0.50

p'₂= 0.40

The parameters of study are the population proportions, if the claim is true then p₁ > p₂

And you can determine the hypotheses as

H₀: p₁ ≤ p₂

H₁: p₁ > p₂

α: 0.05

$Z= \frac{(p'_1-p'_2)-(p_1-p_2)}{\sqrt{p'(1-p')[\frac{1}{n_1} +\frac{1}{n_2}] } } }$ ≈N(0;1)

pooled sample proportion: $p'= \frac{x_1+x_2}{n_1+n_2} =\frac{13+8}{46} = 0.46$

$Z_{H_0}= \frac{(0.5-0.4)-0}{\sqrt{0.46(1-0.46)[\frac{1}{26} +\frac{1}{20}] } } }= 0.67$

p-value: 0.2514

The decision rule is:

If p-value ≤ α, reject the null hypothesis.

If p-value > α, do not reject the null hypothesis.

The p-value: 0.2514 is greater than the significance level 0.05, the test is not significant.

At a 5% significance level you can conclude that the population proportion of math students that obtained at least 80% in the test and had a healthy breakfast is equal or less than the population proportion of math students that obtained at least 80% in the test and didn't have a healthy breakfast.

So having a healthy breakfast doesn't seem to improve the grades of students.

I hope this helps!

5 0

2 years ago

Given: Quadrilateral ABCD is a kite.

Leni [432]

Answer:

Step-by-step explanation:

One

The definition of a kite.

Two

Perpendicular. The diagonals meet at right angles

Three

I don't know if the term is still used, but when I first learned this material (many years ago) we called it the reflexive property.

Four

You found out that <AED = <CED which established that both are right angles. The problem is, you do not have enough information to prove SAS.

AAS is never a dependable reason for proving anything conguent.

HL is really your only choice.

8 0

2 years ago

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