A company makes 625 cell phone cases each day. How many cell phone cases does the company make in 31 days?

A doctor released the results of clinical trials for a vaccine to prevent a particular disease. In these clinical trials, 400 c

Soloha48 [4]

Answer:

We conclude that the vaccine appears to be effective.

Step-by-step explanation:

We are given that a doctor released the results of clinical trials for a vaccine to prevent a particular disease.

The subjects in group 1 (the experimental group) were given the vaccine, while the subjects in group 2 (the control group) were given a placebo. Of the 200 comma 000 children in the experimental group, 38 developed the disease. Of the 200 comma 000 children in the control group, 81 developed the disease.

Let $p_1$ = proportion of subjects in the experimental group who developed the disease.

$p_2$ = proportion of subjects in the control group who developed the disease.

So, Null Hypothesis, $H_0$ : $p_1\geq p_2$ {means that the vaccine does not appears to be effective}

Alternate Hypothesis, $H_A$ : $p_1$ {means that the vaccine appears to be effective}

The test statistics that would be used here Two-sample z proportion statistics;

T.S. = $\frac{(\hat p_1-\hat p_2)-(p_1-p_2)}{\sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} } }$ ~ N(0,1)

where, $\hat p_1$ = sample proportion of children in the experimental group who developed the disease = $\frac{38}{200,000}$ = 0.00019

$\hat p_2$ = sample proportion of children in the control group who developed the disease = $\frac{81}{200,000}$ = 0.00041

$n_1$ = sample of children in the experimental group = 200,000

$n_2$ = sample of children in the control group = 200,000

So, test statistics = $\frac{(0.00019-0.00041)-(0)}{\sqrt{\frac{0.00019(1-0.00019)}{200,000}+\frac{0.00041(1-0.00041)}{200,000} } }$

= -4.02

The value of z test statistics is -4.02.

Now, at 0.01 significance level the z table gives critical values of -2.33 for left-tailed test.

Since our test statistics is less than the critical value of z as -4.02 < -2.33, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the vaccine appears to be effective.

3 0

3 years ago

PLS HURRY I'M BEING TIMED I'LL GIVE BRAINLIEST

blondinia [14]

The basis to respond this question are:

1) Perpedicular lines form a 90° angle between them.

2) The product of the slopes of two any perpendicular lines is - 1.

So, from that basic knowledge you can analyze each option:

a.Lines s and t have slopes that are opposite reciprocals.

TRUE. Tha comes the number 2 basic condition for the perpendicular lines.

slope_1 * slope_2 = - 1 => slope_1 = - 1 / slope_2, which is what opposite reciprocals means.

b.Lines s and t have the same slope.

FALSE. We have already stated the the slopes are opposite reciprocals.

c.The product of the slopes of s and t is equal to -1

TRUE: that is one of the basic statements that you need to know and handle.

d.The lines have the same steepness.

FALSE: the slope is a measure of steepness, so they have different steepness.

e.The lines have different y intercepts.

FALSE: the y intercepts may be equal or different. For example y = x + 2 and y = -x + 2 are perpendicular and both have the same y intercept, 2.

f.The lines never intersect.

FALSE: perpendicular lines always intersept (in a 90° angle).

g.The intersection of s and t forms right angle.

TRUE: right angle = 90°.

h.If the slope of s is 6, the slope of t is -6

FALSE. - 6 is not the opposite reciprocal of 6. The opposite reciprocal of 6 is - 1/6.

So, the right choices are a, c and g.

4 0

3 years ago

Help me answer please

Nastasia [14]

Answer:

Sorry

Step-by-step explanation:

5 0

2 years ago

so i don't understand what we are doing at all. i was gone for a week and i missed when we learned about this and i've just been

kumpel [21]

You will need the fraction on “z” to have a common denominator before you can add the two equations. In this equation the common denominator is 6. So you do not change the left side of the equation however the right side turns into -2/6. Now you can add the z’s together and you can also add the integers together.

After simplification I believe the final answer is 1/2z + 1.

I would maybe wait for someone else to answer so that you can be sure because there are other ways to solve this.

6 0

2 years ago

Read 2 more answers

The triangular numbers are defined by the recursive formula t1 = 1, tn = tn - 1 + n, where n ∈N and n > 1. What are the first

GalinKa [24]

ANSWER

C) 1, 3, 6, 10, 15, 21, 28, 36, 45

EXPLANATION

The recursive formula is,

$t_1=1,t_n=t_{n-1}+n$