All categories

4 years ago

Help with this math.

Mathematics

1 answer:

valentinak56 [21]4 years ago

6 0

Answer:

Step-by-step explanation:

Mean: Add them all up then divide that sum by how many there are.

Median: They are in number order, so that makes median and mode very very nice. For an odd number of points, you choose the middle point, for an even number of points (which we have) take the two and find the average of those two. That is, add the two up then divide them by two, it's basically taking their mean. since there are 20 you take the 10th and 11th numbers.

Mode: Again, super easy since they are in number order, just look for the number that appears the most. If none do, there is no mode. Hint, there is a number that appears twice.

You might be interested in

For the grade-level party, a local bakery donates 40 dozen cookies. There are 157 students in your grade. How many cookies can e

Bad White [126]

Alright so one dozen cookies is 12 cookies. So 40 dozen cookies is 480 cookies (40x12). If there’s 157 students then u divide 480 by 157 which gets u 3.06 cookies per person

8 0

3 years ago

Equation with angle addition please help please

Finger [1]

Answer:

m<CBD = 98

Hope this helps :)

4 0

3 years ago

the strauss insurance company laid off 20% of its employees one year and then increased its staff by 12 1/2% the following year.

jekas [21]

<span>The Strauss Insurance company's net change in staff over the two-year period was a loss of twelve employees. 24 of the original 120 were laid off the first year, leaving 96, and 12 were hired the following year,</span>

7 0

4 years ago

Can someone help me with this ??

stiv31 [10]

My explanation is c because I had this on a test and I got it right , so c

7 0

3 years ago

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

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.

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.

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

4 years ago