Test a claim that the mean amount of lead in the air in U.S. cities is less than 0.036 microgram per cubic meter. It was found that the mean amount of lead in the air for the random sample of 54 U.S. cities is 0.039 microgram per cubic meter and the standard deviation is 0.068 microgram per cubic meter. At α=0.10​, can the claim be​ supported? Complete parts​ (a) through​ (e) below. Assume the population is normally distributed.     (d) Decide whether to reject or fail to reject the null hypothesis.   ▼   Reject Fail to reject H0 because the standardized test statistic ▼   is not is in the rejection region. Part 6 ​(e) Interpret the decision in the context of the original claim.   There ▼   is not is enough evidence at the enter your response here​% level of significance to ▼   rejectreject supportsupport the claim that the mean amount of lead in the air in U.S. cities is ▼   less than equal greater than greater than or equal not equal less than or equal enter your response here microgram per cubic meter. ​(Type integers or decimals. Do not​ round.)

A random sample of 76 eighth-grade​ students' scores on a national mathematics assessment test has a mean score of 273. This test result prompts a state school administrator to declare that the mean score for the​ state's eighth graders on this exam is more than 270. Assume that the population standard deviation is 33. At α=0.02​, is there enough evidence to support the​ administrator's claim? Complete parts​ (a) through​ (e). Part 1 ​(a) Write the claim mathematically and identify H0 and Ha. Choose the correct answer below.   A.) H0​: μ≥270 (claim)       Ha​: μ<270   B.) H0​: μ≤270 (claim)       Ha​: μ>270   C.) H0​: μ=270 (claim)       Ha​: μ>270   D.) H0​:μ≤270       Ha​: μ>270 ​(claim)   E.) H0​: μ<270       Ha​: μ≥270 ​(claim)   F.) H0​: μ=270      Ha​: μ>270 (claim)     (b) Find the standardized z, and its coresponding area      z=_____   (c) Find the P-value P-value =_____   (d) Decide whether to reject or fail the null…

One group of accounting students took a distance learning class, while another group took the same course in a traditional classroom. At α = .10, is there a significant difference in the mean scores listed below?  Exam Scores for Accounting Students Statistic Distance Classroom Mean scores x¯1x¯1 = 9.7 x¯2x¯2 = 10.0 Sample std. dev. s1 = 2.7 s2 = 2.9 Number of students n1 = 23 n2 = 23   Specify the decision rule. (Round your answers to 3 decimal places. A negative value should be indicated by a minus sign.) Find the test statistic tcalc. (Round your answer to 4 decimal places. A negative value should be indicated by a minus sign.) Use Excel to find the p-value. (Round your answer to 3 decimal places.)

The frequency distribution was obtained using a class width of 0.5 for data on cigarette tax rates. Use the frequency distribution to approximate the population mean and population standard deviation. Compare these results to the actual mean μ=​$1.502 and standard deviation σ=​$1.031.

Babies: A sample of 25 one-year-old girls had a mean weight of 24.1 pounds with a standard deviation of 4.3 pounds. Assume that the population of weights is normally distributed. A pediatrician claims that the standard deviation of the weights of one-year-old girls is greater than 7 pounds. Do the data provide convincing evidence that the pediatrician's claim is true? Use the =α0.05 level of significance.

The boiling point of 16 samples of a certain brand of hydrogenated vegetable oil used in a fryer was collected, resulting in Xbar=152.1 degrees. Assume that the distribution of melting point is normal with o=3.20. If the boiling point is different than 150 degrees, then either the oil will be too hot and will burn food or it will be too cool and will not properly cook the food. Is the sample mean significantly different from the target of 150 degrees? Use alpha=0.01 Но: H1: Define critical (rejection) region(s): Calculate the appropriate test statistic: What decision do we make? What this decision means in terms of this problem?

Newspaper Reading Times A survey taken several years ago found that the average time a person spent reading the local daily newspaper was 10.8 minutes. The standard deviation of the population was 3  minutes. To see whether the average time had changed since the newspaper's format was revised, the newspaper editor surveyed 40  individuals. The average time that the 40  people spent reading the paper was 12.4  minutes. At α=0.10 , is there a change in the average time an individual spends reading the newspaper? Find the 90%  confidence interval of the mean. (a) State the hypothesis and identify the claim with the correct hypothesis. :H0     ▼(Choose one)   :H1     ▼(Choose one)   This hypothesis test is a ▼(Choose one) test.       (b)Find the critical value(s). Round the answer to 2  decimal places, if necessary.   Critical values:   (c)Compute the test value. Round the answer to at least 2 decimal places, if necessary. z=   (d)Make the decision.…

Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of 44 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that ? = 7.20 ml/kg for the distribution of blood plasma. (a) Find a 99% confidence interval for the population mean blood plasma volume in male firefighters. What is the margin of error? (Round your answers to two decimal places.)lower limit= upper limit= margin of error= (b) What conditions are necessary for your calculations? (Select all that apply.) the distribution of volumes is normal ? is known the distribution of volumes is uniform n is large ? is unknown c) Find the sample size necessary for a 99% confidence level with maximal margin of error E = 2.80 for the mean plasma…

Newspaper Reading Times A survey taken several years ago found that the average time a person spent reading the local daily newspaper was 10.8 minutes. The standard deviation of the population was 3  minutes. To see whether the average time had changed since the newspaper's format was revised, the newspaper editor surveyed 40  individuals. The average time that the 40  people spent reading the paper was 12.4  minutes. At α=0.10 , is there a change in the average time an individual spends reading the newspaper? Find the 90%  confidence interval of the mean. **NOTE** I already have answer for a,b, and c    (d)Make the decision.   ▼(Choose one) the null hypothesis.       (e)Summarize the results.   There ▼(Choose one) enough evidence to support the claim that there is a change in the average time an individual spends reading the newspaper. Find the 90% confidence interval of the mean. Round the answers to nearest whole number. <u<   (f)Do the results agree?…

Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of 42 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that ? = 8.00 ml/kg for the distribution of blood plasma. (a) Find a 99% confidence interval for the population mean blood plasma volume in male firefighters. What is the margin of error? (Round your answers to two decimal places.) lower limitupper limitmargin of error (b) What conditions are necessary for your calculations? (Select all that apply.) the distribution of volumes is uniform? is knownn is largethe distribution of volumes is normal? is unknown (c) Interpret your results in the context of this problem. We are 99% confident that the true average blood…