Quiz 1 Flashcards
Which of the statements is true?
- Errors and lurking variables are the only sources of variation in data.
- A good statistical study will account for all sources of variability, so that we can be 100% confident in our conclusions.
- We can never be 100% confidante the conclusions of a statistical study.
We can never be 100% confidante the conclusions of a statistical study.
Most data analysis begins by doing what?
- conducting statistical tests and drawing conclusions
- none of the choices are correct
- graphing the data and constructing numerical summaries
- writing surveys and collecting data
Graphing the data and constructing numerical summaries
Opinion polls, such as those performed by Gallup, can best be described as what type of data collection method?
- an experiment
- a sample survey
- an observational study
a sample survey
The bars on a histogram
- can be drawn to touch one another or not; it makes no difference.
- should be drawn with gaps between them to separate the quantities being compared.
- touch one another unless there are no values for that class.
touch one another unless there are no values for that class.
A survey of college students collected information on several variables: distance from home, age, major, gender, and class. The variable “class” is:
- neither quantitative nor categorical
- categorical
- quantitative
categorical
When ordering vinyl replacement windows, the following variables are specified for each window. Which of these variables is quantitative?
- window style—single pane or double pane
- area of the window opening, in square inches
- window style—double-hung, casement, or awning
area of the window opening, in square inches
What is the difference between a histogram and a bar chart?
- A histogram is a more accurate representation of a bar chart.
- A bar chart displays a categorical variable on the horizontal axis, whereas a histogram does not.
- There is no difference; they are exactly the same.
- A bar chart displays a quantitative variable on the horizontal axis, whereas a histogram does not.
A bar chart displays a categorical variable on the horizontal axis, whereas a histogram does not.
A teacher gave a 25‑question multiple‑choice test. After scoring the tests, she computed a mean and standard deviation of the scores. The standard deviation was 0. Based on this information:
- all of the students had the same score.
- about half of the scores were above the mean.
- the teacher must have made a mistake in her computations.
all of the students had the same score.
Does the value of the standard deviation depend on the value of the mean?
- No, because the center of a distribution and the spread are not related.
- Yes, because if the mean gets larger, the standard deviation will also get larger.
- Yes, because the mean must be known in order to calculate the standard deviation.
Yes, because the mean must be known in order to calculate the standard deviation.
The median age of five people in a meeting is 30 years. One of the people, whose age is 50 years, leaves the room. The median age of the remaining four people in the room is:
- 40 years.
- 25 years.
- not able to be determined from the information given.
- 30 years.
not able to be determined from the information given
A group of four friends has a median age of 22 . Three of the friends are ages 20 , 18 , and 24 . The age of the fourth friend must be:
- 24 or older.
- 18 or younger.
- 22 .
- None of these choices are correct; we can’t tell from the information provided.
24 or older.
Which of the following sets of four numbers has the smallest standard deviation?
- 7,8,9,10
- 0,0,10,10
- 5,5,5,6
- 0,1,2,3
5,5,5,6
Which of the following is likely to have a mean that is smaller than the median?
- the scores of students (out of 100 points) on a very difficult exam, in which most scores are low but a few scores are high
- the prices of homes in a large city, where there are lots of relatively inexpensive homes and a few very expensive homes
- the scores of students (out of 100 points) on a very easy exam, in which most scores are high but a few scores are low
- the salaries of all National Football League players, where a few players make much more than most players
the scores of students (out of 100 points) on a very easy exam, in which most scores are high but a few scores are low
A violin student records the number of hours she spends practicing during each of nine consecutive weeks:
6.2 5.0 4.3 7.4 5.8 7.2 8.4 1.2 6.3
What is the mean number of hours spent practicing per week during this period?
- 5.76 hours
- 6.15 hours
- 8.40 hours
- 6.20 hours
5.76 hours
add all the number and divide
