Sincere Garcia
2022-09-29
Answered

What is the z-score of sample X, if $n=169,\mu =42,St.Dev.=39,\phantom{\rule{1ex}{0ex}}\text{and}\phantom{\rule{1ex}{0ex}}E\left[X\right]=12$?

You can still ask an expert for help

cegukwt

Answered 2022-09-30
Author has **10** answers

The z-score for a sample mean is $\frac{\overline{x}-\mu}{\frac{\sigma}{\sqrt{n}}}$

So, here we have $=\frac{12-42}{\frac{39}{\sqrt{169}}}$

$=-\frac{30}{3}=-10$

So, here we have $=\frac{12-42}{\frac{39}{\sqrt{169}}}$

$=-\frac{30}{3}=-10$

asked 2022-10-30

What is the z-score of sample X, if $n=54,\text{}\mu =12,\text{}\text{St.Dev}=30,\text{}{\mu}_{X}=11$?

asked 2022-06-25

I was given a question where I was supposed to find the probability of obtaining y between two scores, however when I input my answer it tells me that I'm wrong, the question is given below along with my answer to the question:

Question

For a normal distribution with sample mean =−19 and standard deviation =6.85 find $p(-16.15\le y\le -15.27)$, where y is a random draw from the normal distribution. Round to 4 decimal places.

My answer

I obtained the z scores for both the y values −15.27 and −16.15 and their respective z scores are 0.5445 and 0.4161. The probability under the curve with a z score of 0.5445 is 0.7054 and the probability under the curve with a z score of 0.4161 is 0.6628. With those two probabilities, I obtained the difference (getting 0.0426) and I put in that answer and was told that I was wrong. Can someone give me insight as to what I'm doing wrong?

Question

For a normal distribution with sample mean =−19 and standard deviation =6.85 find $p(-16.15\le y\le -15.27)$, where y is a random draw from the normal distribution. Round to 4 decimal places.

My answer

I obtained the z scores for both the y values −15.27 and −16.15 and their respective z scores are 0.5445 and 0.4161. The probability under the curve with a z score of 0.5445 is 0.7054 and the probability under the curve with a z score of 0.4161 is 0.6628. With those two probabilities, I obtained the difference (getting 0.0426) and I put in that answer and was told that I was wrong. Can someone give me insight as to what I'm doing wrong?

asked 2022-06-03

Ten randomly selected people were asked how long they slept at night. The mean time

was 7.1 hours, and the standard deviation was 0.78 hour. Find the 95% confidence

interval of the mean time. Assume the variable is normally distributed.

asked 2022-10-29

Can a z-score be negative?

asked 2022-11-18

How do you find the area under the normal distribution curve to the right of z = –3.24?

asked 2022-07-13

I'm curious what the phrase "on average" means. Here is an example:

On average, $30\mathrm{\%}$ were further than ___ kilometers away when they had their accident.

Is $30\mathrm{\%}$ a z-score or is it a mean? Transport Canada was investigating accident records to find out how far from their residence people were to when they got into a traffic accident. They took the population of accident records from Ontario and measured the distance the drivers were from home when they had their accident in kilometers (km). The distribution of distances was normally shaped, with $\mu =30$ kilometers and $\sigma =8.0$ kilometers.

On average, $30\mathrm{\%}$ were further than ___ kilometers away when they had their accident.

Is $30\mathrm{\%}$ a z-score or is it a mean? Transport Canada was investigating accident records to find out how far from their residence people were to when they got into a traffic accident. They took the population of accident records from Ontario and measured the distance the drivers were from home when they had their accident in kilometers (km). The distribution of distances was normally shaped, with $\mu =30$ kilometers and $\sigma =8.0$ kilometers.

asked 2022-08-24

What is the z-score of X, if n = 57, $\mu =35$, SD =5, and X =13?