Question

Detail, with very specific examples of each item, the meaning of the following concepts related to statistical data gathering: Be sure that the concept is first defined, IN YOUR OWN WORDS, and that you use a concrete example (including visual examples) to illustrate your understanding of the statistical concept: Cohort; Placebo; Prospective Study; Retrospective Study; Cluster; Control Group; Mean; Median; Mode; Histogram; Outlier; Pie Chart;

Answer 1

Cohort - a group of people who have common identity based on age . It's effect i.e. cohort effect is variation in sone characterstics that nfluences the result of research ndirectly due to age related changes.

eg Children of today and children of 1950s have different characterstic so any research for a particular trait will yield different result.

Placebo -- an item of no therapeutic value of itself , is disguised as some intended treatment. when given to client or target , may generate sone effect similar to actual treatment.

eg mixing water in vodka glass with flavor of vodka but no alcohol to test how person behave.

Prospective study. It watches for outcomes over duration of study and assess the risk factor .

eg assessing risk factor of smoking in develoonent of cardiovascular disease.

Retrospective study - it looks backwards for examining the cause for an outcome establ ished at start of study.

eg establishing cause for cancer which has already develooedd.

Cluster a study where similar kind of subjects are grouped together.

eg grouping subject into the young , adult and okdo

Control Group is the group which is not provided with any treatment but us used to compare with those who have got treatment to measure effect of treatment.

eg measuring effect of a medicine on reducing pain . Control group received no medicine while other group received. Later both level of pain compared to conclude effectiveness.

Mean Averaging all the items .

eg scores of 3 5 9 has mean of 17/3

Median Arranging no in increasing order , then the middle item is median for odd no of item while middle two for even.

eg 3 , 5 , 9 , median is 5

Mode the item which is repeated most no of times

eg 4, 7, 5 7 ,9 5, 7. Mode is 7.

Histogram a display of statistical information that combine depicting a level combined with frequency .

eg different bar showing a level of marks , say 60-70 , and no of student getting this mark ,say 20 students.

Outlier an observation different from all other ibservationoin study.

eg -- in study of iq , if an iq cones out to be 45 whereas all others belonged between 70 to 120.

Pie chart it is statistical circular representation where each arc is proprtional to numerical value it shows .