Mock Test

A study was designed to assess the impact of deforestation on forestland usage in Yosemite National Park. A survey was sent to 583 forest owners from this region, and 342 were returned.

Identify the population and the sample for this study

• The population is all forest owners in the region and the sample is the 583 forest owners to whom the survey was sent

• The population is the 583 forest owners to whom the survey was sent and the sample is the 342 forest owners who responded.

• The population is the 342 forest owners who responded to the survey and the sample is all forest owners in the region.

  
  

• The population is all inhabitants of Yosemite National Park and the sample is the 583 forest owners to whom the survey was sent.

Numerous scientific studies indicate that calcium is an essential mineral for the formation and maintenance of strong, healthy bones. An inadequate supply of calcium in the diet is broadly believed to contribute to weak, porous bones, increasing the risk of a hip fracture, especially in the elderly. Calcium can be obtained from several sources, including soybeans, many leafy green vegetables, and dairy products.

The scatterplot and superimposed regression line depict the relationship between the annual incidence rate of hip fracture and the annual rate of dairy consumption for a sample of forty nations.

The regression analysis reveals a highly significant positive linear correlation between the variables. The sample linear correlation coefficient, 𝑟, is .759. Note that this positive relationship is opposite from what you would expect.

• When the relationship between two variables is nonlinear, the actual relationship between the variables is typically the opposite as that indicated by the sample linear correlation coefficient

• Because the regression line does not have a meaningful 𝑦-intercept, it is inappropriate to interpret the sample linear correlation coefficient to indicate a positive relationship

• The sample size of 4040 world nations is not large enough to establish any relationship. The linear correlation and regression analysis are invalid

• There is at least one lurking variable that correlates with both dairy consumption and hip fractures

Suppose the manager of a gas station monitors how many bags of ice he sells daily along with recording the highest temperature each day during the summer. The data are plotted with temperature, in degrees Fahrenheit (°F), as the explanatory variable (x) and the number of ice bags sold that day as the response variable (y). The least squares regression (LSR) line for the data is y-hat=−114.05+2.17x.

On one of the observed days, the temperature was 90 °F and 75 bags of ice were sold. Determine the number of bags of ice predicted to be sold by the LSR line, y-hat , when the temperature is 90 °F. Enter your answer as a whole number, rounding if necessary

• 64

• 81

• 76

• 94

First quartile is also known as

• Lower quartile

• Upper quartile

• Median

• Geometric Mean

Which most accurately describes a correlational method?

• It looks at the relationship or association between variables

• It aims to determine the probability of a particular future outcome

• It seeks to uncover causal relationships

• It analyses the differences between groups

What is a random sample?

• A set of items drawn from a population, where some items are more likely than others to end up in the sample.

• A set of items drawn from a population, where each item in the population has a random chance of ending up in the sample.

• A set of items drawn from a population, where each item in the population has an equal chance of ending up in the sample.

• A set of items drawn from a population on an adhoc, unstructured, basis.

Many states have programs for assessing the skills of students in various grades. The National Assessment of Educational Progress (NAEP) is one such program. In a recent year the mean mathematics score for forth‑graders was 250, and the standard deviation was 30. Assuming that these scores are approximately Normally distributed, 𝑁(250,30), use the 68–95–99.768–95–99.7 rule to give a range of scores that includes 68% of these students.

• (150,220)

• (220,280)

• (190,310)

• (160,340)

In a recent year the mean SAT score was 525, and the standard deviation was 20. Assuming that these scores are approximately Normally distributed, 𝑁(525,20), use the 68–95–99.7 to find the percentage of students that scored 505 to 565.

• 68%

• 99.7%

• 81.5%

• 34%

when is the z considered an unusual value

• when z is less than -3 or greater than +3

• when z is less than -1.5 or greater than +1.5

• when z is less than -2 or greater than +2

• cant be determined