A pet pharmaceutical company releases a new treatment, claiming to control fleas in cats for an average of 60 days per dose.

im stupid. honestly. just help me pls. this is probably really easy but i aint done any maths in over a month so ion remember ho

KATRIN_1 [288]

Answer:

19 coins

Step-by-step explanation:

We know that mean is the sum of all the elements divided by the number of elements there are: m = t/n, where m is the mean, t is the total sum, and n is the number of elements.

Here, we are given the mean number of coins for all 27 + 18 = 45 children is 16, so m = 16 and n = 45. Then:

m = t/n

16 = t/45

t = 720

This t means that the total number of coins that all the boys and girls have is 720 coins.

Now, we also know the mean number of coins for the boys only, which is 14. Since there are 27 boys, then:

m = t/n

14 = t/27

t = 378

This t means the total number of coins all the boys have.

Subtracting 378 from 720, we get 342, which is the total number of coins the girls have. We also know there are 18 girls, so:

m = t/n

m = 342 / 18 = 19

Thus, the mean is 19 coins.

7 0

3 years ago

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The Salk polio vaccine experiment in 1954 focused on the effectiveness of the vaccine in combating paralytic polio. Because it w

sdas [7]

Answer:

Step-by-step explanation:

Hello!

The variables of interest are:

X₁: Number of cases of polio observed in kids that received the placebo vaccine.

n₁= 201299 total children studied

x₁= 110 cases observed

X₂: Number of cases of polio observed in kids that received the experimental vaccine.

n₂= 200745 total children studied

x₂= 33 cases observed

These two variables have a binomial distribution. The parameters of interest, the ones to compare, are the population proportions: p₁ vs p₂

You have to test if the population proportions of children who contracted polio in both groups are different: p₂ ≠ p₁

a)

H₀: p₂ = p₁

H₁: p₂ ≠ p₁

α: 0.05

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

Sample proportion placebo p'₁= x₁/n₁= 110/201299= 0.0005

Sample proportion vaccine p'₂= x₂/n₂= 33/200745= 0.0002

Pooled sample proportion p'= (x₁+x₂)/(n₁+n₂)= (110+33)/(201299+200745)= 0.0004

$Z_{H_0}= \frac{(0.0002-0.0005)-0}{\sqrt{0.0004[\frac{1}{201299} +\frac{1}{200745} ]} }= -4.76$

This test is two-tailed, using the critical value approach, you have to determine two critical values:

$Z_{\alpha/2}= Z_{0.025}= -1.96$

$Z_{1-\alpha /2}= Z_{0.975}= 1.96$

Then if $Z_{H_0}$ ≤ -1.96 or if $Z_{H_0}$ ≥ 1.96, the decision is to reject the null hypothesis.

If -1.96 < $Z_{H_0}$ < 1.96, the decision is to not reject the null hypothesis.

⇒ $Z_{H_0}$ = -4.76, the decision is to reject the null hypothesis.

b)

H₀: p₂ = p₁

H₁: p₂ ≠ p₁

α: 0.01

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

The value of $Z_{H_0}$ = -4.76 doesn't change, since we are working with the same samples.

The only thing that changes alongside with the level of significance is the rejection region:

$Z_{\alpha /2}= Z_{0.005}= -2.576$

$Z_{1-\alpha /2}= Z_{0.995}= 2.576$

Then if $Z_{H_0}$ ≤ -2.576or if $Z_{H_0}$ ≥ 2.576, the decision is to reject the null hypothesis.

If -2.576< $Z_{H_0}$ < 2.576, the decision is to not reject the null hypothesis.

⇒ $Z_{H_0}$ = -4.76, the decision is to reject the null hypothesis.

c)

Remember the level of significance (probability of committing type I error) is the probability of rejecting a true null hypothesis. This means that the smaller this value is, the fewer chances you have of discarding the true null hypothesis. But as you know, you cannot just reduce this value to zero because, the smaller α is, the bigger β (probability of committing type II error) becomes.

Rejecting the null hypothesis using different values of α means that there is a high chance that you reached a correct decision (rejecting a false null hypothesis)

I hope this helps!

8 0

3 years ago

Which algebraic expression has a term with a coefficient of 3?

Mariulka [41]

Answer:

D. 3y+1

Step-by-step explanation:

The coefficient is the number in front of the variable

3y has a coefficient of 3

3 ( y-6) has a factor of 3 since it is multiplied by the other term ( y-6)

4 0

3 years ago

ron wants to buy a video game with a selling price of $60, on sale for 50% off. The sales tax in 4.5% state is . How much wil

dybincka [34]

Answer:

Yes, he can.

Step-by-step explanation:

To find the sale, you need to times the sale percentage by the original price so

60 x 0.50 = 30

Then you subtract the original price by the sale price so

60 - 30 = 30

So the with the sale, the price is $30.

Now the tax

Do the same

30 x 0.045 = 1.35

Now instead of subtracting you add so

30 + 1.35 = $31.35

Yes, he can afford it.

4 0

2 years ago

A group of students and workers entering a metro station were asked whether they were riding the bus or the subway. The two-way

BaLLatris [955]

Because this is a two-way table, the answer would be that 166 people were polled in total. Why? Well, there are lots of corresponding patterns leading up to this answer. We can easily find the answer by looking at the problem two different ways:

1st way: Identifying the missing solution by rows.

27 + 21 = 48 and 42 + 76 = 118, so we can find the missing value by adding 69 and 97 to get 166.

2nd way: Identifying the missing solution by columns.

27 + 42 = 69 and 21 + 76 = 97, so we can find the missing value by adding 48 and 118 to get 166, our missing solution.

Your final answer: 166 people were polled. Your answer would be D. If you need to better understand this, let me know and I will gladly assist you.

4 0

2 years ago

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