Point Estimate

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college. What is the point estimate?

• 75

• 105.2

• 10

• 0.90

Given the interval (1.2, 1.8), what is the point estimate and the margin of error? 

• 1.5, 0.6

• 1.5, 0.3

• 1.2, 0.3

• 1.2, 0.6

A __________ is a specific value used to estimate a population parameter.

The best point estimate of the population mean is the __________.

In a survey conducted by a researcher in economics, 5 groups of residents of Masagana City were asked about their expenses in a day. The mean expenses in pesos for each group are as follows: 588, 632, 575, 740, and 610. What is the point estimate of the population mean?

• P786.25

• P629.00

• P524.16

• P449.28

Given a confidence interval, how do you determine the value of the point estimate?

• Find the middle of the interval - (lower value + upper value)/2.

• Find the range of the interval and divide by 2.

• Use the lower end of the interval.

• You can't determine the point estimate from the confidence interval.

The general form of a confidence interval is

• point estimate x 2

• point estimate + margin of error

• point estimate - margin of error

• point estimate +/- margin of error

A local pizza shop claims that they deliver pizzas in 30 minutes or less. The 95% confidence interval obtained from a random sample of 12 deliveries is [26.8,41.0].

Calculate the point estimate used to create this interval.

• 7.1 minutes

• 13.4 minutes

• 33.9 minutes

• 30.7 minutes

Answer explanation

(26.8 + 41)/2 = 33.9

A magazine reported that 66% of dog owners greet their dog before their spouse of children when they arrive home. A random sample of 40 dog owners was obtained and a 95% confidence interval was calculated as [0.68, 0.78]. Calculate the point estimate that was used to create this interval

• 78%

• 5%

• 73%

• 66%

Harry is running for town council. He wants to estimate the likelihood of winning. A random sample of registered voters was asked if they planned on voting for Harry. The 95% confidence interval is [0.32, 0.38]. What is the point estimate that was used to create this interval?

• 0.70

• 0.35

• 0.03

• 0.65