Calculating Population Based on Sample

Explain the concept of inference in the context of sampling distribution of slopes.

• Inference involves calculating the mean of the sample slopes

• Inference is not relevant in sampling distribution of slopes

• Inference in the context of sampling distribution of slopes involves making conclusions about the population slope based on the sample slope.

• Inference is only applicable to large sample sizes

The Gallup Poll interviews 1600 people. Of these, 18% say that they jog regularly. The news report adds: “The poll had a margin of error of plus or minus three percentage points at a 95% confidence level.” You can safely conclude that

• 95% of all Gallup Poll samples like this one give answers within + 3% of the true population value.

• the percent of the population who jog is certain to be between 15% and 21%.

• 95% of the population jog between 15% and 21% of the time.

• we can be 95% confident that the sample proportion is captured by the confidence interval.

• if Gallup took many samples, 95% of them would find that 18% of the people in the sample jog.

A smaller, more manageable representation of a larger group

• Random Assignment

• Average

• Population

• Sample

A piece of data that allows us to make inferences about the population

• Descriptive Statistic

• Inferential Statistic

• Average

• Mode

A survey is carried out at Penn State Altoona to estimate the proportion of all undergraduate students living at home during the current term. Of the 3,838 undergraduate students enrolled at the campus, a random sample of 100 was surveyed. What is the population of the study?

• All the 3,838 undergraduate students enrolled at the campus

• The 100 who were surveyed

• All the students in universities across America

• All students living at home in the current term.

You want to design a study to estimate the proportion of students at your school who agree with the statement, "The student government is an effective organization for expressing the needs of students to the administration." You will use a 95% confidence interval, and you would like the MOE to be 0.05 or less. The minimum sample size required is...

• 22

• 271

• 385

• 769

• 1795

The Gallup Poll interviews 1600 people. Of these, 18% say that they jog regularly. The news report adds: “The poll had a margin of error of plus or minus three percentage points at a 95% confidence level.” You can safely conclude that…

• 95% of all Gallup Poll samples like this one give answers within ±3% of the true population value.

• The percent of the population who jog is certain to between 15% and 21%.

• 95% of the population jog between 15% and 21% of the time.

• We can be 95% confident that the sample proportion is captured by the confidence interval.

• If Gallup took many samples, 95% of them would find that 18% of the people in the sample jog.

You are going to create a 95% confidence interval for a population proportion and want the margin of error to be no more than 0.05. Historical data indicate that the population proportion has remained constant at about 0.7. What is the minimum size random sample you need to construct this interval?

• 385

• 322

• 274

• 275

• 323

You want to calculate a 94% confidence interval for a population proportion from a sample of n = 38. What is the appropriate critical z*?

• 1.555, -1.555

• 1.881, -1.881

• 1.94, -1.94

• 1.592, -1.592