4) The basic shape of a -distribution is
A) skewed to the right since one of the characteristics of a -distribution is that the -distribution is skewed to the right.
B)skewed to the left is false since as per the characteristics of -distribution the graph or basic shape of -distribution is skewed to the right.
C)bell-shaped is false because the characterisitcs of -distribution state that the basic shape of -distribution is skewed to the right but when df>90(degrees of freedom), the curve approximates to a normal distribution.
D)Uniform is false because the characteristics of -distribution state that the basic shape of -distribution is skewed to the right.
Hence the basic shape of a -distribution is skewed to the right.
5) We are given the following values
n=865(no.of voters surveyed), x=408(no. of voters favored approval of an issue before the legislature)
(0.4716763006 actually)
q'=1-p'=1-0.472=0.528
Since CL(confidence level) is 0.97, we know that and
The area to the right of z0.015 is 1-0.015=0.985.
From the areas of the standard normal distribution table when you look for the value 0.985, you obtain the critical value of 2.17.
Hence (critical value of z at 3% level of significance)
The 97% confidence interval for true proportion is given by the formula,
Substituting the values in the above equation, we get the following confidence interval,
is the required confidence interval.
Hence 97% confidence interval for true proportion is,
0.272<p<0.672
7)
a)The original claim is that the standard deviation of hardness indexes for all such bolts is greater than 30 as evidenced by the line "Test the claim that the standard deviation of hardness indexes for all such bolts is greater than 30".
b) The null hypothesis is,
i.e., the standard deviation of hardness indexes for all bolts is equal to 30.
c) The alternate hypothesis is,
i.e., the standard deviation of hardness indexes for all bolts is greater than 30
d) We are given the following values and are asked to perform hypothesis test
Since this is a single variance hypothesis test, we use chi-square test for single variance test to conduct the hypothesis test.
n=12(no.of bolts), s=41.7(standard deviation of hardness index of all bolts), (from null and alternate hypothesis).
Test statistic under H0
=21.253(21.2531 actually)
Hence the test statistic for -test for single variance is 21.253
e) The p-value for -test statistic is 0.0308.
Question 4 2 pts What is the basic shape of the x2 - distribution? Skewed to...
When 12 bolts are tested for hardness, their indexes have a standard deviation of 41.7. Test the claim that the standard deviation of the hardness indexes for all such bolts is greater than 30.0. Use a 0.025 level of significance. Assume that the population is normally distributed and the sample has been randomly selected.
S. Find the critical value or values of χ2 based on the given information. (1 point) Hi: σ < 0.629 n- 19 α 0.025 8.231 8.907 3 1.526 7.015 0 Use the traditional method to test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected. Select the appropriate response. 29. For randomly selected adults, IQ scores are normally distributed with a standard deviation of 15. The scores of 14 randomly selected...
> Question 9 3 pts In a randomized, double-blind, placebo-controlled trial of children, echinacea was tested as a treatment for upper respiratory infections in children. "Days of fever" was one criterion used to measure effects. Among 337 children treated with echinacea, the mean number of days with fever was 0.81, with a standard deviation of 1.50 days. Among 370 children given a placebo, the mean number of days with fever was 0.64 with a standard deviation of 1.16 days. Assuming...
Question 8 2 pts A sprinkler manufacturer claims that the average activating temperatures is at least 134 degrees. To test this claim, you randomly select a sample of 32 systems and find the mean activation temperature to be 133 degrees. Assume the population standard deviation is 3.3 degrees. Find the standardized test statistic and the corresponding p-value O z-test statistic - -1.71, p-value-0.0432 O z-test statistic -1.71, p-value -0.0865 O z-test statistic -1.71, p-value- 0.0865 O z-test statistic - 1.71,...
Question 4 0/3 pts 5399 Detail: You wish to test the following claim (H) at a significance level of a = 0.005. H: = 52.2 H: < 52.2 You believe the population is normally distributed, but you do not know the standard deviation. You obtain a sample of size n = 57 with mean M = 50.3 and a standard deviation of SD = 17.7. What is the test statistic for this sample? (Report answer accurate to three decimal places.)...
question 2-c and 2-d 2 .c) Test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected. A manufacturer uses a new production method to produce steel rods. A random sample of 17 steel rods resulted in lengths with a standard deviation of 4.7 cm. At the 0.10 significance level, test the claim that the new production method has lengths with a standard deviation different from 3.5 cm, which was the standard...
Question 2 > 0/3 pts 399 Details You wish to test the following claim (H) at a significance level of a = 0.001. H.: = 84.9 H: > 84.9 You believe the population is normally distributed and you know the standard deviation is o = 10.4 You obtain a sample mean of M = 85.5 for a sample of size n = 74. What is the test statistic for this sample? (Report answer accurate to three decimal places.) test statistic...
Question 19 6 pts For Questions 19-22.consider the following: The mayor of a town has proposed a plan for the annexation of a new community. A political study took a sample of 1,600 voters in the town and found that 69% of the residents favored annexation. Using the data, a political strategist wants to test the daim that the percentage of residents who favor annexation is at least 65% What is the alternative hypothesis? Hap<0.65 O Hapa 065 O Haps...
Question 3 0/3 pts 399 Details You wish to test the following claim (H) at a significance level of a 0.002 H: = 55.3 H: 55.3 You believe the population is normally distributed, but you do not know the standard deviation. You obtain a sample of size n = 28 with mean M = 56.9 and a standard deviation of SD = 7.5. What is the test statistic for this sample? (Report answer accurate to three decimal places.) test statistic...
Question 5 0/3 pts 5399 Details You wish to test the following claim (H) at a significance level of a = 0.02. Hu = 50.7 H: #50.7 You believe the population is normally distributed, but you do not know the standard deviation. You obtain a sample of size n = 410 with mean M = 46.7 and a standard deviation of SD = 20.7. What is the test statistic for this sample? (Report answer accurate to three decimal places.) test...