True/False Questions

Descriptive statistics involves characterizing the obtained data.

Question 21 pts

True experiments involve the manipulation of variables by the investigator.

Question 31 pts

The method of authority is opposed to the scientific method.

Question 41 pts

Data are an indispensable part of scientific method.

Question 51 pts

In an experiment conducted to determine the effect of testosterone on aggression, testosterone is the independent variable.

Question 61 pts

When doing summation, the number above the summation sign indicates the term ending the summation and the number below indicates the beginning term.

Question 71 pts

If IQ was measured on a ratio scale, and John had an IQ of 40 and Fred an IQ of 80, it would be correct to say that Fred was twice as intelligent as John.

Question 81 pts

Measurement is always approximate with a continuous variable.

Question 91 pts

In rounding, if the remainder beyond the last digit is greater than 1/2, add one to the last digit. If the remainder is less than 1/2, leave the last digit as it is.

Question 101 pts

The number of students in a class is an example of a continuous variable.

Question 111 pts

The real limits of a discrete variable are those values that are above and below the recorded value by one half of the smallest measuring unit of the scale.

Question 121 pts

In grouping scores, the wider the intervals, the more information that is lost.

Question 131 pts

Any percentile point for a distribution of scores must have a value equal to one of the scores.

Question 141 pts

If a curve is negatively skewed, most of the scores occur at the higher values and the curve tails off toward the lower end of the horizontal axis.

Question 151 pts

A frequency distribution of grouped scores is used for distributions that have relatively few scores to stretch them out.

Question 161 pts

A stem and leaf diagram contains more information than a histogram.

Question 171 pts

The median and the 50th percentile rank score will always have the same value.

Question 181 pts

When calculating the population standard deviation, we use N  1 in the denominator.

Question 191 pts

Central tendency describes the central location of the set of scores.

Question 201 pts

If the number of raw scores is odd, the median is always the score in the middle position.

Question 211 pts

In a bell-shaped distribution, the mean, median and mode will be equal.

Question 221 pts

For data that are not normally distributed, the standard deviation will sometimes be negative.

Question 231 pts

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

Question 241 pts

The normal curve reaches the horizontal axis in 4 standard deviations above and below the mean.

Question 251 pts

It is impossible to have a z score of 30.2

Question 261 pts

The area beyond a z score of 1.12 is the same as the area beyond a z score of 1.12.

Question 271 pts

A raw score that is 1 standard deviation above the mean of the raw score distribution will have a z score of 1.

Question 281 pts

Correlation implies causation.

Question 291 pts

The range of a correlation coefficient is 0 to +1.

Question 301 pts

Pearson r requires that the data be of interval or ratio scaling.

Question 311 pts

Rho is used where one or both variables are at least of interval scaling.

Question 321 pts

In general, the regression line for predicting X given Y is the same as the regression line for predicting Y given X.

Question 331 pts

An imperfect relationship generally yields exact prediction.

Question 341 pts

Properly speaking, we should limit our predictions to the range of the base data.

Question 351 pts

To do linear regression, there must be paired scores on two variables.

Question 361 pts

If the correlation between two variables is 1.00, the standard error of estimate equals 0.

Question 371 pts

When a sampled score is put back in the population before selecting the next score, this process is called sampling without replacement.

Question 381 pts

Probability values range from 0 to 1.

Question 391 pts

The Addition Rule concerns one of several possible events.

Question 401 pts

When a variable is continuous, p(A) equals the area under the curve corresponding toA divided by the total area under the curve.

Question 411 pts

If an event is certain to occur, its probability of occurrence equals 1.00.

Question 421 pts

We always evaluate just the specific result obtained in the experiment.

Question 431 pts

The sign test analyzes both the magnitude and direction of the data.

Question 441 pts

If the result turns out to be in the direction opposite to a directional H1, we must conclude by retaining H0.

Question 451 pts

It is impossible to prove with certainty the truth of H1 when using sample data.

Question 461 pts

If alpha is made more stringent, beta increases.

Question 471 pts

If H0 is true, as the power of the experiment increases, the probability of rejecting H0increases.

Question 481 pts

Increasing N increases the probability of a Type II error.

Question 491 pts

Other factors held constant, a one-tailed test is more powerful than a two-tailed test.

Question 501 pts

High power is desirable in an experiment.

Question 511 pts

Decreasing beta will generally cause  to increase.

Question 521 pts

The degrees of freedom equal N  1 for the t test for single samples.

Question 531 pts

The t test requires that the sampling distribution of t be normally distributed.

Question 541 pts

Generally speaking, the more confidence we have that the interval contains the population mean, the larger is the interval.

Question 551 pts

In general, if r = 0, then  = 0.