It takes Diego 130 of an hour to complete a lap on a circular bike track. The track is 15 mile long. What is Diego’s bike speed?

The U.S. Center for Disease Control reports that the mean life expectancy was 47.6 years for whites born in 1900 and 33.0 years

inn [45]

Answer:

b. The null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

c. Student's t distribution, as it is a two-sample test for the difference between means.

d. Test statistic t = 5.42.

P-value = 0

e. They appear to be significantly different, as the sample data gives strong evidence that the difference is greater than 0.

Step-by-step explanation:

This is a hypothesis test for the difference between populations means.

The claim is that the mean life spans in the county is significantly different for whites and nonwhites.

Then, the null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

The significance level is 0.05.

The sample 1 (white), of size n1=124 has a mean of 45.3 and a standard deviation of 12.7.

The sample 2 (non-white), of size n2=82 has a mean of 34.1 and a standard deviation of 15.6.

The difference between sample means is Md=11.2.

$M_d=M_1-M_2=45.3-34.1=11.2$

The estimated standard error of the difference between means is computed using the formula:

$s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{12.7^2}{124}+\dfrac{15.6^2}{82}}\\\\\\s_{M_d}=\sqrt{1.301+2.968}=\sqrt{4.269}=2.066$

Then, we can calculate the t-statistic as:

$t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{11.2-0}{2.066}=\dfrac{11.2}{2.066}=5.42$

The degrees of freedom for this test are:

df=n_1+n_2-2=124+82-2=204

This test is a two-tailed test, with 204 degrees of freedom and t=5.42, so the P-value for this test is calculated as (using a t-table):

$\text{P-value}=2\cdot P(t>5.42)=0.0000002$

As the P-value (0.0000002) 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 mean life spans in the county is significantly different for whites and nonwhites.

4 0

2 years ago

What is the answer and how to solve it and give me the right answer

Keith_Richards [23]

Answer:

2/10 or in its simplest form 1/5

Step-by-step explanation:

there is 2 grey marbles so 2/10 (there is 10 marbles altogether)

so half of 2 is 1 and half of 10 is 5

so the answer is 1/5

7 0

2 years ago

Read 2 more answers

Item 18 You and your friend are selling tickets to a charity event. You sell 7 adult tickets and 16 student tickets for $120. Yo

Jobisdone [24]

$4

You can get this by setting up 2 equations. One for you and one for your friend. Each should have a cost equation. Let x = adult and y = student.

You: 7x + 16y = 120
Friend: 13x + 9 = 140

Solve using any method.

6 0

2 years ago

Read 2 more answers

Use the Central Limit Theorem to find a mean given a probability Question A video game company sells an average of 132 games a m

aev [14]

Answer:

The number of games must a store sell in order to be eligible for a reward is 135.

Step-by-step explanation:

Let the random variable X represent the number of video games sold in a month by the sores.

The random variable X has a mean of, μ = 132 and a standard deviation of, σ = 9.

It is provided that the company is looking to reward stores that are selling in the top 7%.

That is, $P (\bar X > \bar x) = 0.07$ .

The z-score related to this probability is, z = 1.48.

Compute the number of games must a store sell in order to be eligible for a reward as follows:

$z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}$

$\bar x=\mu+z\cdot \sigma/\sqrt{n}$

$=132+1.48\times (9/\sqrt{36})\\\\=132+2.22\\\\=134.22\\\\\approx 135$

Thus, the number of games must a store sell in order to be eligible for a reward is 135.

5 0

2 years ago

Multiplication scale

DerKrebs [107]

Answer:

here is a multiplication scale

Step-by-step explanation:

8 0

2 years ago