Question

A scientist claims that the mean water temperature in the Florida Everglades is greater than 30 °C. . He records water temperatures at the same station over a 61-day period. The temperature is recorded at the same time each day, and the mean is found to be 30.4°C. Assume that standard deviation = 1.7 C.

Construct a 95% confidence interval for the population mean.

Interpret the interval.

Is the scientist’s claim consistent with the data? Explain. No credit for “YES/NO” answer only.

Find the sample size necessary for a 95% confidence interval with a maximal margin of error of 0.35.

Answer #1

The mean water temperature downstream from a discharge pipe at a
power plant cooling tower should be no more than 100°F. Past
studies has shown that the standard deviation of temperature is
2°F. The water temperature was measured on 10 randomly chosen days,
and the results are shown below:
96.15 97.81 97.09 95.06 99.46
100.03 99.74 98.85
95.08 98.71
a. State the null hypothesis and alternative hypothesis for the
above problem.
b. Is there evidence that the water temperature is...

Question 4:
An article in Wikipedia claims that the mean body
temperature of adults is less than 98.6° F. This goes against
everything you’ve ever been taught, so you gather 565 healthy
adults and observe a mean body temperature of 98.2°F, with the
sample standard deviation of 2.6°F. Test the article’s claim at a
5% level of significance.
If the problem is a confidence interval:
Show whether the criteria for approximate normality are
met. (1 point)
Summarize the sample statistics....

The personnel office at a large electronics firm regularly
schedules job interviews and maintains records of the interviews.
From the past records, they have found that the length of a first
interview is normally distributed, with mean μ = 34
minutes and standard deviation σ = 6 minutes. (Round your
answers to four decimal places.)
(a) What is the probability that a first interview will last 40
minutes or longer?
(b) Six first interviews are usually scheduled per day. What...

A bottled water distributor wants to determine whether the mean
amount of water contained in 1-gallon bottles purchased from a
nationally known water bottling company is actually 1 gallon. You
know from the water bottling company specifications that the
standard deviation of the amount of water is
.03 gallon. You select a random sample of 50 bottles, and the
mean amount of water per 1-gallon bottle is 0.993 gallon. Complete
parts (a) through (d) below.
a. Is there evidence that...

Question #1
How hot is the air in the top (crown) of a hot air balloon?
Information from Ballooning: The Complete Guide to Riding the
Winds, by Wirth and Young (Random House), claims that the air in
the crown should be an average of 100°C for a balloon to be in a
state of equilibrium. However, the temperature does not need to be
exactly 100°C. What is a reasonable and safe range of temperatures?
This range may vary with the...

1. A city official claims that the proportion of all commuters
who are in favor of an expanded public transportation system is
50%. A newspaper conducts a survey to determine whether this
proportion is different from 50%. Out of 225 randomly chosen
commuters, the survey finds that 90 of them reply yes when asked if
they support an expanded public transportation system. Test the
official’s claim at α = 0.05.
2. A survey of 225 randomly chosen commuters are asked...

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