Question

Acid rain, caused by the reaction of certain air pollutants with rainwater, is a growing problem in the United States. Pure rain falling through clean air registers a pH value of 5.7 (pH is a measure of acidity: 0 is acid; 14 is alkaline). Suppose water samples from 90 rainfalls are analyzed for pH, and x and s are equal to 3.9 and 0.8, respectively. Find a 99% confidence interval for the mean pH in rainfall. (Round your answers to three decimal places.)_______ to _______

Interpret the interval:

1)There is a 99% chance that an individual sample mean will fall within the interval.

2) In repeated sampling, 99% of all intervals constructed in this manner will enclose the population mean. 9

3) 9% of all values will fall within the interval.

4) There is a 1% chance that an individual sample mean will fall within the interval.

5) In repeated sampling, 1% of all intervals constructed in this manner will enclose the population mean.

What assumption must be made for the confidence interval to be valid?

1)The standard deviation must be less than 10.

2)The sample mean must be greater than 5.

3) The sample must be random.

4)There must be at least 100 samples.

5)The sampling distribution must be symmetrical.

Answer #1

Here n=90, as sample size is sufficient large so as per central limit theorem distribution of sample mean is normal.

Hence we will use z distribution to find CI

z value for 99% CI is 2.58 as

As s=0.8, margin of error is

So CI is

2) In repeated sampling, 99% of all intervals constructed in this manner will enclose the population mean.

5. The sampling distribution must be symmetrical as for data to be normally distributed distribution needs to be symmetrical

Acid rain, caused by the reaction of certain air pollutants with
rainwater, is a growing problem in the United States. Pure rain
falling through clean air registers a pH value of 5.7 (pH is a
measure of acidity: 0 is acid; 14 is alkaline). Suppose water
samples from 80 rainfalls are analyzed for pH, and x and
s are equal to 3.1 and 0.4, respectively. Find a 99%
confidence interval for the mean pH in rainfall. (Round your
answers to...

Acid rain, caused by the reaction of certain air pollutants with
rainwater, is a growing problem in the United States. Pure rain
falling through clean air registers a pH value of 5.7 (pH is a
measure of acidity: 0 is acid; 14 is alkaline). Suppose water
samples from 40 rainfalls are analyzed for pH, and x and
s are equal to 3.2 and 0.9, respectively. Find a 99%
confidence interval for the mean pH in rainfall. (Round your
answers to...

Acid rain—rain with a pH value less than 5.7, caused by the
reaction of certain air pollutants with rainwater—is a growing
problem in the United States. Pure rain falling through clean air
registers a pH value of 5.7 (pH is a measure of acidity: 0 is acid;
14 is alkaline). A sample of n = 30 rainfalls produced pH
readings with x = 3.7 and s = 0.5. Do the data
provide sufficient evidence to indicate that the mean pH...

Find a 90% confidence interval for a population mean ?
for these values. (Round your answers to three decimal places.)
(a)
n = 130, x = 0.85, s2 =
0.084
to
(b)
n = 40, x = 20.1, s2 =
3.86
to
(c)
Interpret the intervals found in part (a) and part (b).
There is a 10% chance that an individual sample proportion will
fall within the interval.In repeated sampling, 10% of all intervals
constructed in this manner will enclose...

Find a 90% confidence interval for a population mean ?
for these values. (Round your answers to three decimal places.)
(a)
n = 145, x = 0.88, s2 =
0.084
to
(b)
n = 70, x = 25.6, s2 =
3.49
to
(c)
Interpret the intervals found in part (a) and part (b).
There is a 10% chance that an individual sample proportion will
fall within the interval.There is a 90% chance that an individual
sample proportion will fall within...

A random sample of n = 300 observations from a binomial
population produced x = 223 successes. Find a 90%
confidence interval for p. (Round your answers to three
decimal places.)
to
Interpret the interval.
In repeated sampling, 10% of all intervals constructed in this
manner will enclose the population proportion.There is a 90% chance
that an individual sample proportion will fall within the
interval. In repeated sampling, 90% of all
intervals constructed in this manner will enclose the population
proportion.There...

Acid rain – rain with a pH value less than 5.7 caused by the
reaction of certain air pollutants with rainwater – is a growing
problem in the US.
Suppose a sample of n = 40 rainfalls produced pH readings with a
sample mean of 3.7 and a sample standard deviation of .5
A) Write the null and alternative hypothesis for this
problem.
B) The data for the z-test is shown here. What is your conclusion?
Support your answer with...

The following data represent the pH of rain for a random sample
of 12 rain dates. A normal probability plot suggests the data could
come from a population that is normally distributed. A boxplot
indicates there are no outliers. Complete parts a) through d)
below.
5.58
5.72
4.38
4.80
5.02
5.03
4.74
5.19
4.61
4.76
4.56
5.30
(a) Determine a point estimate for the
population mean.
A point estimate for the population mean is
(Round to two decimal places as...

The following data represent the pH of rain for a random sample
of 12 rain dates. A normal probability plot suggests the data could
come from a population that is normally distributed. A boxplot
indicates there are no outliers. Complete parts (a) through (d)
below.
DATA: 5.20, 5.72, 4.38, 4.80, 5.02, 5.16, 4.74, 5.19, 5.34,
4.76, 4.56, 4.68
(a) Determine a point estimate for the population mean.
A point estimate for the population mean is _______???? (round
to 2 decimal...

The following data represent the pH of rain for a random sample
of 12 rain dates. A normal probability plot suggests the data could
come from a population that is normally distributed. A boxplot
indicates there are no outliers. Complete parts (a) through (d)
below.
5.58
5.72
4.8
4.80
5.02
4.68
4.74
5.19
5.34
4.76
4.56
5.54
(a) Determine a point estimate for the population mean.
A point estimate for the population mean is _________.
(Round to two decimal places...

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