The basic idea underlying sampling is to select a representative sample, from which the investigator can make inferences to the population.

A. True B. False

A.True

A sample is said to be random when it is not representative of the population.

B. False

3. A random sample is one in which 50% of the elements of a population have equal chances of being sampled.

A representative sample:

A. Consist of at least 500 cases

B. Must be a random sample

C. Is defined as the inverse of the square root of the sample size

D. Reflects precisely the crucial dimensions of a population

Stratified random sampling involves the selection of the most accessible elements of the population.

If a sample is representative, then it yields valid data for making generalizations about the population from which it was drawn.

A. True

If a population contains 50% males and 50% females, and our sample 10% males and 90% females, then our sample is said to be biased.

If a sample is large (say n>500) then the sample must be representative.

A sample size increases:

A. The sampling error decreases

B. The population become more accessible

C. The sample becomes more biased

The larger the sample size, the larger the sampling error.

If the sample size is halved, the sampling error will be doubled.

When you take a patient’s blood pressure daily, you are in fact sampling from a population of potential blood pressure readings.

Say that it is known that coronary disease occurs twice as frequently among males as females and three times more commonly among over 50 year-olds than those under 50. Given a stratified sample of 120, how many subjects would you expect to be female and under 50?

A. 60

B. 40

C. 30

D. 10

A random sample is one in which:

A. All the elements had an equal chance of selection

B. A chance method was used to select the elements included in a sample

C. Both statements are true

Within the following statements select one which you believe to be true. An ordinal variable is one for which:

A. The data are discrete and can take one of many values

B. The data are continuous and follow an ordered sequence

C. The categories of response are ordered

Which of the following measures of the variable ‘weight’ is nominal?

A. Weight in kg

B.Weight as obese/overweight/normal/underweight/grossly underweight

C. Weight as ‘normal against pathological’ (obese or grossly underweight)

D. Weight as percentage overweight in relation to “healthy” weight

Select one of the following variables measured on a nominal scale.

A. Height in cm

B. Ethnic group

C. Education categorized as primary school, secondary school, bachelor degree

D. Age in years

The readings ’64 kilograms” is a value on a(n):

A. ratio scale

B. interval scale

C. ordinal scale

D. nominal scale

A sample by convenience is always representative.

An interval scale has an absolute zero.

The levels of measurements which have equal intervals are the ordinal and nominal scales.

Ordinal scales are generally preferable to interval scales.

Ordinal measures involve rank-ordering the values of a variable.

Nominal scales do not have the characteristic of ‘distinctiveness’ (categories).

The gender of patients is an example of a(n): A. ratio scale

B. nominal scale

D. interval scale

“The tenth” is a value on a(n):

If a population contains 50% males and 50% females, and a sample 10% males and 90% females, then such sample is said to be biased.

In a patient record system, patients are randomly assigned a unique identification number. These numbers represent a (n):

A. nominal scale

B. ratio scale

C. interval scale

D. ordinal scale

An auto analyst is conducting a satisfaction survey, sampling from a list of 10,000 new car buyers. The list includes 2,500 Ford buyers, 2,500 GM buyers, 2,500 Honda buyers, and 2,500 Toyota buyers. The analyst selects a sample of 400 car buyers, by randomly sampling 100 buyers of each brand. What is the sample type?

A. Simple random sample

B. Stratified random sample

C. Systematic random sample

Which of the following statements are true? (Check one)

A. Categorical variables are the same as qualitative variables.

B. Quantitative variables can be continuous variables.

z scores express how many standard deviations a particular score is from the mean A. True B. False

The total area under the standard normal curve is always 1.0.

The area of normal curve between any two designated z scores expresses the proportion or percentage of cases falling between the two points.

A. True B False

About 10% of scores fall 3 standard deviations above the mean.

50% of scores fall between z = 0.5 and z = - 0.5.

A True B. False

In a normal curve, approximately 34% of the scores fall between z=0 an z=-1

Numerous human characteristics are distributed approximately as a normal curve

The height of the rectangle in a histogram is proportional to class frequency and class width A. True B False

Which of the following statements is true?

A. A z score indicates how many standard deviations a raw score is above or below the mean

B. The mean of a standard normal distribution is always 0

C. All the above statements are true

In an anatomy test, your result is equivalent to z score of -0.2. What does this z score imply?

A You performed very well when compared to others

B Your result was slightly above average

C. Your result was slightly below average

State whether the data reflecting the age at death of individuals in the general population are likely to be skewed to the right, skewed to the left or symmetrical.

A Symmetrical

B Skewed to the right (positively skewed)

C. Skewed to the left (negatively skewed)

Select the statement which you believe to be true. The Normal distribution:

A. Is a family of distributions which can have a variety of means and standard deviations

B. Is the distribution of a variable measured on healthy individuals

C. Has a mean of zero and a standard deviation of one

D. Is skewed to the right

Frequency distribution is another expression for a bar chart

A histogram can be used instead of a pie chart to display categorical data

A True B False

B False

A histogram is similar to a bar chart but there are no gaps between the bars

A histogram can be used to display either a frequency or a relative frequency distribution

A histogram is used to show the relationship between two variables

A bar chart is used to display categorical data A. True B False

A bar chart can only be used to display data which have a symmetrical distribution

A bar chart contains separate bars, with the length of each bar being proportional to the relevant frequency or relative frequency

Select all of the following type(s) of figures that would be appropriate for illustrating the distribution of heights of children in a class

A. Histogram

B. Box-plot

C. Dot-plot

D. All listened types of figures are appropriate

Select all of the following type(s) of figures that would be appropriate for illustrating the distribution of blood groups in a sample of adults

A. Bar chart

B. Pie chart

C. Both types are appropriate

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