Test a claim that the mean amount of carbon monoxide in the air in U.S. cities is less than 2.31 parts per million. It was found that the mean amount of carbon monoxide in the air for the random sample of 66 cities is 2.37 parts per million and the standard deviation is 2.09 parts per million. At =0.10, can the claim besupported? Complete parts(a) through(e) below. Assume the population is normally distributed.

(a) Identify the claim and state H0 and Ha. Which of the following correctly states H0 and Ha?

H0:

HA:

(Type integers or decimals. Do notround.)

The claim is the

The claim is the ? hypothesis.

null or

alternative

(b) Use technology to find the criticalvalue(s) and identify the rejectionregion(s).

The criticalvalue(s) is/are t0= ??

(Use a comma to separate answers as needed. Round to two decimal places asneeded.)

Choose the graph which shows the rejection region.

(c) Find the standardized teststatistic, t.

The standardized test statistic is t= ??

(Round to two decimal places asneeded.)

(d) Decide whether to reject or fail to reject the null hypothesis.

reject or fail to reject?? H0 because the standardized test statistic is not or is in the rejection region.

(e) Interpret the decision in the context of the original claim.

There is or is not? enough evidence at the ?% level of significance to support or

reject? the claim that the mean amount of carbon monoxide in the air in U.S. cities is ?

greater than or equal

a.not equal

b.less than or equal

c.equal

d.greater than

e.less than

?(type integers or decimals. Do not round.) parts per million.

parts per million.

(Type integers or decimals. Do notround.)