We would be looking at the first question all parts here as:
Q12) a) From standard normal tables, we have here:
P(Z < 0.385) = 0.65
Therefore, P(Z < 0.385) = 1 - 0.65 = 0.35
Therefore 0.385 is the required z score here which cuts off the top 35% of the normal curve.
b) From standard normal tables, we have here:
P(Z < -0.842) = 0.2
Therefore the cuttoff value here is computed as:
= Mean -0.842*Std Dev
= 75 -0.842*5
= 70.79
Therefore 70.79 is the required cutoff value here.
c) From standard normal tables, we have here:
P(Z < 0.674) = 0.75
Therefore, due to symmetry, we have here:
P(-0.674 < Z < 0.674) = 0.5
Therefore -0.674, 0.674 are the required z scores here which cut off the middle 50% of the normal curve here.
12-13 show work 12. Using a normal distribution and z score formula answer the following questions:...
12 and 13 12. Using a normal distribution and z score formula answer the following questions: a. Find the Z-score that cuts off the top 35% of the nornval curve b. Find the data value to the nearest whole number that cuts off the bottom 20% of the curve given that the mean is 75 and sample standard deviation is 5. c. Find the z scores that cut off the middle 50% of the normal curve. 13. This question is...
12. Using a normal distribution and z score formula answer the following questions: a. Find the Z-score that cuts off the top 35% of the nornval curve b. Find the data value to the nearest whole number that cuts off the bottom 20% of the curve given that the mean is 75 and sample standard deviation is 5. c. Find the z scores that cut off the middle 50% of the normal curve. 13. This question is worth 4 points...
12. Using a normal distribution and z score formula answer the following questions: a. Find the Z-score that cuts off the top 35% of the nornval curve b. Find the data value to the nearest whole number that cuts off the bottom 20% of the curve given that the mean is 75 and sample standard deviation is 5. c. Find the z scores that cut off the middle 50% of the normal curve.
13. This question is worth 4 points only. A statistics professor has surveyed 225 NCC students to determine the cost of their textbooks for the semester. He determined that the sample mean was $425 with a population standard deviation of $75 i) Determine the standard error of a 95% confidence interval Determine the 95% confidence interval (round to the nearest whole number) iii) Determine the 99% confidence interval (round to the nearerst whole #) ii)
13. This question is worth 4 points only. A statistics professor has surveyed 225 NCC students to determine the cost of their textbooks for the semester. He determined that the sample mean was $425 with a population standard deviation of $75 i) Determine the standard error of a 95% confidence interval ii) Determine the 95% confidence interval (round to the nearest whole number) iii) Determine the 99% confidence interval (round to the nearerst whole #)
13. This question is worth 4 points only. A statistics professor has surveyed 225 NCC students to determine the cost of their textbooks for the semester. He determined that the sample mean was $425 with a population standard deviation of $75 i) Determine the standard error of a 95% confidence interval ii) Determine the 95% confidence interval (round to the nearest whole number) iii) Determine the 99% confidence interval (round to the nearerst whole #)
11. Use the following table to answer the questions X Y 7 18 8 23 10 28 13 32 37 16 41 20 45 52 14 26 a. Make a scatterplot and determine the relationship between X and Y b. Find the linear regression equation Y' = (round a and b to the nearest hundredth ) c. Find r and r’ to the nearest hundredth d. Use the equation found in part b to determine X to the nearest whole...
7. Determine whether a normal distribution or a normal distribution or t distribution should be used or whether neither of should be used to construct a confidence interval for the mean. (Section 6.2) Circle the correct answer. in a random sample of 22 families, the mean weekly food expense was $95.60 with a sample standard deviation of $22.50. Assume the weekly food expense is normally distributed. A) Normal distribution B) t-distribution C) Neither For a sample of 20 IQ scores...
1) Given a standard normal distribution, find the probability of having a z score higher than 1.67 ```{r} ``` 2) Given that test scores for a class are normally distributed with a mean of 80 and variance 36, find the probability that a test score is lower than a 45. ```{r} ``` 3) Given a standard normal distribution, find the Z score associated with a probability of .888 ```{r} ``` 4) Find the Z score associated with the 33rd quantile...
statistics itl 5 LTE Confidence Interval for the P... DOCX -16 KB Close Confidence Interval for the Population Mean l. Determine the critical values for 80%, 90%, 95%, and 99%; 2. Construct 80%, 90%, 95%, and 99% confidence interval for the population mean given that the standard deviation of the population is 900 and the sample mean is 425 and the sample consist of 100 points of data 3. Find the T interval for the following: Construct 80% 90%. 95%,...