An environmental scientist obtains a sample of water from an irrigation canal that contains a certain...
An environmental scientist obtains a sample of water from an irrigation canal that contains a certain type of bacteria at a concentration of 6 per milliliter. Find the standard deviation of the number of bacteria in a 3-milliliter sample.
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4.2
6
18
2.4
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An environmental scientist obtains a sample of water from an
irrigation canal that contains a certain...
5. An environmental scientist wanted to test if the mean concentration of carbon trioxide in blue...
5. An environmental scientist wanted to test if the mean concentration of carbon trioxide in blue water exceeds the safe level of 22 blops per cubic centimeter of water. She collected 64 samples of blue water, and obtained a sample mean of 26.935 blops and a sample standard deviation of 14 blops. At significance level 0.05, can it be concluded that the true mean concentration exceeds 22 blops?
A research scientist wants to know how many times per hour a certain strand of bacteria...
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 8.9 reproductions and the population standard deviation is known to be 1.8. If a sample of 449 was used for the study, construct the 98 % confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.
A research scientist wants to know how many times per hour a certain strand of bacteria...
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 10.2 reproductions and the population standard deviation is known to be 2.1. If a sample of 1731 was used for the study, construct the 99% confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.
A research scientist wants to know how many times per hour a certain strand of bacteria...
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 5.25.2 reproductions and the population standard deviation is known to be 2.12.1. If a sample of 775775 was used for the study, construct the 90%90% confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.
9 4 An environmental engineer has obtained a bacteria culture from a municipal water sample and...
9 4 An environmental engineer has obtained a bacteria culture from a municipal water sample and allowed the bacteria to grow within a petri dish. The following data were obtained: Time (min) Bacteria Concentration (ppm) Time (min) Bacteria Concentration (ppm) 0 6 6 63 1 7 102 2 15 8 153 3 19 9 220 32 10 328 5 42 Enter the data into an Excel worksheet and plot the data using arithmetic scale, semi-log coordinates, and log-log coordinates. Use...
A research scientist wants to know how many times per hour a certain strand of bacteria...
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. He wants to construct the 95 % confidence interval with a maximum error of 0.19 reproductions per hour. Assuming that the mean is 6.4 reproductions and the standard deviation is known to be 1.8, what is the minimum sample size required for the estimate? Round your answer up to the next integer
You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample...
You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample of 35 bacteria reveals a sample mean of ¯ x = 72 hours with a standard deviation of s = 4.2 hours. You would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.65 hours at a 99% level of confidence. What sample size should you gather to achieve a 0.65 hour margin of error?...
An environmental group is conducting a study to determine whether dolphins in a certain region are...
An environmental group is conducting a study to determine
whether dolphins in a certain region are ingesting unhealthy levels
of arsenic. A marine biologist classifies arsenic levels greater
than 7.0 parts per million as unhealthy. The arsenic levels in a
random sample of 28 dolphins in the region are measured and
recorded, and the data are shown in the stemplot.
Key: 2|4 = 2.4 parts per million
Part A: What proportion of dolphins in the
sample have arsenic levels classified...
You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample...
You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample of 30 bacteria reveals a sample mean of ū = 74 hours with a standard deviation of s = 4.2 hours. You would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.65 hours at a 90% level of confidence. What sample size should you gather to achieve a 0.65 hour margin of error? Round...
Question 2 (4.2 points) In a certain city, the monthly water bill amount is normally distributed...
Question 2 (4.2 points) In a certain city, the monthly water bill amount is normally distributed with mean 25 and standard deviation 15. A sample of 36 bills was selected. What is the probability that the average water bill amount for the sample was between 28.7 and 30? Write only a number as your answer. Round to 4 decimal places (for example 0.0048). Do not write as a percentage. Your Answer:
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 8.9 reproductions and the population standard deviation is known to be 1.8. If a sample of 449 was used for the study, construct the 98 % confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.
9 4 An environmental engineer has obtained a bacteria culture from a municipal water sample and allowed the bacteria to grow within a petri dish. The following data were obtained: Time (min) Bacteria Concentration (ppm) Time (min) Bacteria Concentration (ppm) 0 6 6 63 1 7 102 2 15 8 153 3 19 9 220 32 10 328 5 42 Enter the data into an Excel worksheet and plot the data using arithmetic scale, semi-log coordinates, and log-log coordinates. Use...
A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. He wants to construct the 95 % confidence interval with a maximum error of 0.19 reproductions per hour. Assuming that the mean is 6.4 reproductions and the standard deviation is known to be 1.8, what is the minimum sample size required for the estimate? Round your answer up to the next integer
An environmental group is conducting a study to determine
whether dolphins in a certain region are ingesting unhealthy levels
of arsenic. A marine biologist classifies arsenic levels greater
than 7.0 parts per million as unhealthy. The arsenic levels in a
random sample of 28 dolphins in the region are measured and
recorded, and the data are shown in the stemplot.
Key: 2|4 = 2.4 parts per million
Part A: What proportion of dolphins in the
sample have arsenic levels classified...
You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample of 30 bacteria reveals a sample mean of ū = 74 hours with a standard deviation of s = 4.2 hours. You would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.65 hours at a 90% level of confidence. What sample size should you gather to achieve a 0.65 hour margin of error? Round...
Question 2 (4.2 points) In a certain city, the monthly water bill amount is normally distributed with mean 25 and standard deviation 15. A sample of 36 bills was selected. What is the probability that the average water bill amount for the sample was between 28.7 and 30? Write only a number as your answer. Round to 4 decimal places (for example 0.0048). Do not write as a percentage. Your Answer:
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