HELP PLEASE WITH 5 QUESTIONS!!!

Assume that we want to construct a confidence interval. Do one of the following, as appropriate:_________.

Answer:

B. z Subscript alpha divided by 2 zα/2 = 1.96.

Step-by-step explanation:

We are given that we want to construct a confidence interval. For this, the summary statistics for randomly selected weights of newborn girls:

n = 236, $\bar x$ = 30.3 hg, s = 7.2 hg. The confidence level is 95%.

As we can clearly see here that the population standard deviation is unknown and the sample size is also very large.

It has been stated that when the population standard deviation is unknown, we should use t-distribution but since the sample size is very large so we can use z distribution also as it is stated that at very large samples; the t-distribution corresponds to the z-distribution.

Here, $\alpha$ = level of significance = 1 - 0.95 = 0.05 or 5%

$\frac{\alpha}{2}=\frac{0.05}{2}$ = 0.025 or 2.5%

So, the value of $Z_(_\frac{\alpha}{2} _)$ in the z table is given as 1.96 with a 2.5% level of significance.

3 0

3 years ago

P(more than z=-2.59)is?

romanna [79]

Neither p or z ISNT A NUMBER SO DO ONE WITH A NUMBER THAT QUESTIPON IS WRONG
EEEEEEE

7 0

4 years ago

Will mark brainliest! Questions are in the picture!

alexdok [17]

Answer:

52.9 inches .

Step-by-step explanation:

Given that the triangular indentation has an area of 100 in.² and the base and height of this traingle are represented by expressions 3x and x+3 respectively . We need to find out the perimeter to the nearest tenth.

As we know that the area of triangle is ,

$\rm\longrightarrow Area_{\triangle}=\dfrac{1}{2}(base)(height)$

Substituting the respective values,

$\rm\longrightarrow 100\ =\dfrac{1}{2}(x+3)(3x)\\\\\rm\longrightarrow 2(100) = 3x(x+3)\\\\\rm\longrightarrow200 = 3x^2+9x\\\\\rm\longrightarrow 3x^2+9x-200=0$

On using the Quadratic formula , we have;

$\rm\longrightarrow x =\dfrac{-9\pm\sqrt{9^2-4(3)(-200)}}{2(3)} \\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{81+1200}}{6}\\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{1281}}{6}$

On simplifying above , we will get ,

$\rm\longrightarrow x = 6.802,-9.802$

Since sides can't be negative, therefore,

$\rm\longrightarrow\underline{\underline{ x =6.802}}$

Therefore ,

$\rm\longrightarrow Base = 3x =3(6.802)in = 20.406\ in\\$
$\rm\longrightarrow Height = x +3=6.802+3=9.802\ in$

Next let's find out the hypotenuse using Pythagoras theorem, as ;

$\rm\longrightarrow h=\sqrt{ b^2+p^2}\\$

$\rm\longrightarrow h =\sqrt{ (20.406)^2+(9.802)^2}\\$

$\rm\longrightarrow h =\sqrt{416.40+96.07}\\$

$\rm\longrightarrow h = 22.63\ in$

Now we may find perimeter as ,

$\rm\longrightarrow P = p + b + h \\$

$\rm\longrightarrow P = (22.63 + 9.802 + 20.406)in.$

$\\\rm\longrightarrow P = 52.89 \ in.\\$

$\rm\longrightarrow \underline{\underline{ Perimeter = 52.9\ in .}}$

8 0

3 years ago

Identify the type of observational study (cross-sectional, retrospective, or prospective) described below. A research company

Sindrei [870]

Answer:

Prospective study

Step-by-step explanation:

A cross-sectional study, also known as transverse study, is a type of observational study that analyzes data from a population at a specific point in time. This kind of observation is used if cases cannot be identified a priori or if the prevalence of the disease or condition needs to be determined.

Cohort studies are when two or more groups of subjects are followed over time to see if they develop some disease or if some event occurs, there are two type of cohort studies, prospective and retrospective. Prospective studies (or follow-up studies) follow subjects with different exposures until some point in time where something happens or the study ends, retrospective studies use historical data to make comparisons based on risk factors or exposures that occurred before the events.

Considering the information given and the observational study exposed to the question, we can conclude that we are talking about a prospective study because data is collected over the next 10 years.

I hope you find this information useful and interesting! Good luck!

7 0

3 years ago

I dont get it plz help

adelina 88 [10]

Answer:

its either b or d

Step-by-step explanation:

4 0

3 years ago

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