Mathematics, 26.03.2020 20:57 paaaaaaapi

A study measured the LDL cholesterol level in 49 subjects. The subjects were then treated with raw garlic for six months. The mean change in the 49 subjects was a reduction of 0.4 with a standard deviation of 21.0 (assume this is the actual standard deviation for the population, not and estimate). Find a 95% confidence interval for the mean change in LDL cholesterol after a treatment of garlic. Do you think garlic is effective in reducing LDL cholesterol? Source: Article by Gardner, et al., from Archives of Internal Medicine, Vol. 167.

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Answer from: broang23

$-0.4-1.96\frac{21}{\sqrt{49}}=-6.28$

$-0.4+1.96\frac{21}{\sqrt{49}}=5.48$

So on this case the 95% confidence interval would be given by (-6.28;5.48) For this case since the confidence interval contains the 0 we don't have enough evidence to conclude that the garlic is effective reducing the LDL cholesterol

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Let X the random variable who represent the mean change in the LDL

$\bar X=-0.4$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=21$ represent the population standard deviation

n=49 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$-0.4-1.96\frac{21}{\sqrt{49}}=-6.28$

$-0.4+1.96\frac{21}{\sqrt{49}}=5.48$

Answer from: Quest

answer: c

step-by-step explanation: because you don't have to draw a point of intersection. couldyou give me brainliest?

Iwill give brainliest plz asap. which action is not a step in using paper folding to find the midpo

Answer from: Quest

on a coordinate grid, point a is at (−4.0, −2.4) and point b is at (4.0, −2.4). point b is a reflection of point a across the –axis. input either a lowercase x or i think is the right awnser

step-by-step explanation:

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