I know what you are
Interpret a correlation of .8 versus .2
Both are positive. .8 is strong, .2 is weak.
Recently, Erica took an IQ test and found that she an IQ of 120. The average IQ for her age group is 1, with a standard deviation of 15. How can we interpret her score?
She has an IQ that is 1.33 above the mean. Therefore, her IQ is relatively large and falls within a little higher than the upper end 68% of all scores on a normal distribution
I am using categorical variables only. Which type of chart should I use?
Bar chart
Two researchers a test that determines if a disease exists. The test has a specificity of .70 and a sensitivity of .95, with a prevalence rate of 78%. In a sample of 1000 persons drawn, some people receive a negative test result. Of this number, how many people (as a percentage) who receive a negative test result actually do not have the disease?
79.7%
What is the variability of a correlation of .64?
.4096 or 40.96%
What is the empirical rule for a skewed distribution?
There isn’t one, 68-95-99.7 only works for a normal distribution
I am using continuous variables. Which type of chart should I use?
Histogram or line graph, depending on the nature of the data
Two researchers a test that determines if a disease exists. The test has a specificity of .60 with a prevalence rate of 78%. In a sample of 1000 persons drawn, some people receive a negative test result. Of this number, how many people (as a percentage) who receive a negative test result actually do not have the disease?
There is not enough information to calculate the answer
Divya and Alex are conducting an experiment measuring the effects of eating carrots on growth in height of lemurs. The height in lemurs are the ________ variable, and height in lemurs is a __________ variable.
Response; continuous
On a normal distribution, Diamond scores a 72% on her final exam, whereas Grayson scores a 56%. The mean is 65% with a standard deviation of 5. How many standard deviations away from the mean are they? Who has the greater distance?
Grayson is -1.8 standard deviations below the mean, whereas Diamond’s about +1.40 above the mean. They are roughly 16% point away from each other. Grayson is the farthest away.
What are the benefits of using a box plot vs. a stem-and-leaf plot? Draw out the charts with a data set you generate to explain your answer.
*Answers will vary
I conduct a study that finds that the mean difference of two groups falls within a confidence interval range of -.0001 to 5. What conclusion may I make?
Retain the null because zero is within this range. There is no difference between these groups.
Karen collects a sample and finds that her distribution has a very large standard deviation relative to the mean. How can she correct for this?
Increase her sample size
My five number summary has, you guess it, 5 numbers to it:
There are two outliers, set at 2 and 60, respectively. Taking this into consideration, what is the range of the first 25% of the scores in a box plot? What about 2 to 20?
It’s 25% for both; we don’t add in outliers when measuring a box plot. While they can throw-off the distribution (e.g., make it skewed), in this case, we would say that because the numbers are so spread out on both ends, that there is so much variability that we would need to collect a larger sample to counteract this.
I believe in you!
Bella Swan and Cedric Diggory are dating and decide to cast votes in the 2020 election of America’s Next Top Model between Albus Dumbledore, Donald Trump, and a Cumquat. According to a news poll, there is a projected voter pool of 20% to 40% of voters voting for Albus Dumbledore, 50% to 70% voting for Trump, and 70% to 100% voting for the Cumquat. Who is likely to win the most votes? Who should they vote for?
Trump and the Cumquat are in a statistical tie that falls above Albus Dumbledore’s range. So, it is likely that one of the two will be America’s Next Top Model. Bella and Cedric should vote for whomever they please because they are independent vampires/people.