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Firlakuza [10]
4 years ago
10

According to a statistical​ journal, the average lengths of a newborn is 19.6 inches with a standard deviation of 1.2 inches. Th

e distribution of lengths is approximately Normal. What is the probability that a newborn baby will have a length of 18 inches or​ less? (Please include steps)
Mathematics
1 answer:
avanturin [10]4 years ago
3 0

Answer:

9.18%

Step-by-step explanation:

First, find the z-score.

z = (x − μ) / σ

z = (18 − 19.6) / 1.2

z = -1.33

Use a chart or calculator to find the probability:

P(Z < z) = 0.0918

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A doctor released the results of clinical trials for a vaccine to prevent a particular disease. In these clinical​ trials, 200,0
CaHeK987 [17]

Answer:

1) No, there is  not  enough evidence to support the claim that the vaccine was effective (P-value=0.104) .

The null and alternative hypothesis are:

H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2< 0

being the subindex 1 for the experimental group and subindex 2 for the control group.

2) Test statistic z=-1.26

Step-by-step explanation:

This is a hypothesis test for the difference between proportions.

The claim is that the vaccine was effective.

Then, the null and alternative hypothesis are:

H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2< 0

The significance level is 0.01.

The sample 1 (experimental group), of size n1=100000 has a proportion of p1=0.0002.

p_1=X_1/n_1=21/100000=0.0002

The sample 2 (control group), of size n2=100000 has a proportion of p2=0.0003.

p_2=X_2/n_2=30/100000=0.0003

The difference between proportions is (p1-p2)=-0.0001.

p_d=p_1-p_2=0.0002-0.0003=-0.0001

The pooled proportion, needed to calculate the standard error, is:

p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{21+30}{100000+100000}=\dfrac{51}{200000}=0.00026

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

s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.00026*0.99974}{100000}+\dfrac{0.00026*0.99974}{100000}}\\\\\\s_{p1-p2}=\sqrt{0+0.0000000025}=\sqrt{0.0000000051}=0.000071

Then, we can calculate the z-statistic as:

z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{-0.00009-0}{0.000071}=\dfrac{-0.00009}{0.000071}=-1.26

This test is a left-tailed test, so the P-value for this test is calculated as (using a z-table):

P-value=P(z

As the P-value (0.104) is bigger than the significance level (0.01), the effect is not significant.

The null hypothesis failed to be rejected.

There is  not  enough evidence to support the claim that the vaccine was effective.

6 0
3 years ago
The quotient obtained when an integer is divided by its additive inverse is ________________.
LenaWriter [7]

Answer: -1

Step-by-step explanation: Let the integer be x

It's additive inverse = -x

= x / -x = -1

7 0
3 years ago
I'LL GIVE BRAINLIEST!!!!!!!!!!
Xelga [282]

Answer:B.

Step-by-step explanation:

7 0
3 years ago
Read 2 more answers
in 1990 there were about 5.4 billion people in the world. if the population has been growing at 1.95% per year, estimate the yea
kompoz [17]

Answer:

2011

Step-by-step explanation:

Here is the formula.

A=P(1+r)^{n}

A = Final Value

P = Starting Value

R = Rate

N = Time in Years

A = 8,000,000,000

P = 5,400,000,000

R = 0.0195

N = Time in Years

Solve for n.

20.35 Years from 1990; so sometime in 2011 the population would be 8 billion.

6 0
2 years ago
BASED ON THE GRAPH, WHICH STATEMENT IS CORRECT?
abruzzese [7]

Answer:

i would go for a but im not really sure. sorry if incorrect

Step-by-step explanation:

3 0
3 years ago
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