1) You\'re an undercover biological weapons agent who has been given an unknown
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Question
1) You're an undercover biological weapons agent who has been given an unknown liquid - you suspect that it is just sugar water (because you drank some by accident - you know you're not supposed to have food or drink in the lab, but you do it all the time, and it tasted sweet - plus you didn't die!) One of the tests you need to run is to see if it contains protein (remember, foreign proteins can cause severe immune responses which can be a powerful biological weapon). You set up 3 test tubes each with 10mL of the following: distilled water, gelatin solution and the unknown.
The distilled water is clear, the gelatin solution is clear with a beige tint, and the unknown is clear.
You use Biuret's Reagent - a dark blue dye which will turn a liquid sample purple in the presence of protein.
When Biuret's Reagen is added to the unknown, predict what color you expect it to become if the unknown is just sugar water: [a] (no change | blue | purple).
2)You included both a positive and negative control for this experiment. The gelatin is the [c] control.
3)If the positive control turns blue, it means:
there is no protein present
this control is no good - need to troubleshoot and perform the experiment again
there is protein present
this control is doing exactly what its supposed to do - you can have confidence that the results of the unknown will be accurate
4) The Cambridge Study in Delinquent Development was undertaken in north London (U.K.) to investigate the links between criminal behavior in young men and the socioeconomic factors of their upbringing (Farrington 1994). A cohort of 395 boys was followed for about 20 years, starting at the age of 8 or 9. All of the boys attended six schools located near the research office. The following table shows the total number of criminal convictions by the boys between the start and end of the study.
Frequency
What type of table is this? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
What is the variable presented in this table? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
How many boys had exactly 2 convictions by the end of the study? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
What percentage of boys had no conviction? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67% (round to nearest whole percentage - report as percentage, not as fraction)
Is this frequency distribution symmetric or skewed? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
Is it unimodal or bimodal? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
What is the mode? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
Are there outliers? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67% (yes or no)
Does the sample of boys used in this study represent a random sample of British boys? symmetricalskewedstrip chartcontingency tablefrequency table02601421unimodalbimodalnumber of convictionssocioeconomic factorsyesno33%50%67%
there is no protein present
this control is no good - need to troubleshoot and perform the experiment again
there is protein present
this control is doing exactly what its supposed to do - you can have confidence that the results of the unknown will be accurate
Explanation / Answer
Statistics solution :
A.What type of table is this? Contingency Table (since it is a frequency table with categories mentioned alongside)
B.What is the variable presented in this table? Frequency
C. How many boys had exactly 2 convictions by the end of the study? 21( 3rd row giving the frequency of the boys having 2 convictions between the start and end of study )
D.What percentage of boys had no conviction? 265/395 = 0.6709
E.Is this frequency distribution symmetric or skewed? Skewed ( positively skewed since if we draw the frequency curve for the data, the curve will have highest peak in the Right side and will have subsequent much lesser values in the left side )
F.Is it unimodal or bimodal? Unimodal ( since the highest frequency here = 265 )
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