Stats Review

1
Stats Review
2
Identify the appropriate statistic

• A researcher randomly assigns five individuals to
  receive a new experimental procedure and five to
  a control condition. At the end of the study, all
  10 are measured. Scores for those in the
  experimental group were 7, 6, 9, 7, and 6. Scores
  for those in the control group were 5, 2, 4, 3,
  and 6.

3
Identify the appropriate statistic

• A researcher randomly assigns five individuals to
  receive a new experimental procedure and five to
  a control condition. At the end of the study, all
  10 are measured. Scores for those in the
  experimental group were 7, 6, 9, 7, and 6. Scores
  for those in the control group were 5, 2, 4, 3,
  and 6.
• Independent measures t-test

4
Identify the appropriate statistic

• An experiment compares the effects of four
  treatments, giving each treatment to 20
  participants and then assessing their performance
  on a standard measure.

5
Identify the appropriate statistic

• An experiment compares the effects of four
  treatments, giving each treatment to 20
  participants and then assessing their performance
  on a standard measure.
• One way ANOVA

6
Identify the appropriate statistic

• A medical researcher has heard anecdotal evidence
  that certain anti-depressive drugs can have the
  positive side-effect of lowering neurological
  pain in those individuals with chronic,
  neurological back pain, when administered in
  doses lower than those prescribed for depression.
  The researcher identifies 3 well-known,
  anti-depressive drugs which might have this
  positive side-effect, and labels them Drug A,
  Drug B and Drug C. The researcher then recruits a
  group of 60 individuals with a similar level of
  back pain and randomly assigns them to one of
  three groups - Drug A, Drug B or Drug C treatment
  groups - and prescribes the relevant drug for a 4
  week period. At the end of the 4 week period, the
  researcher asks the participants to rate their
  back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. The
  researcher wishes to compare the levels of pain
  experienced by the different groups at the end of
  the drug treatment period.

7
Identify the appropriate statistic

• A medical researcher has heard anecdotal evidence
  that certain anti-depressive drugs can have the
  positive side-effect of lowering neurological
  pain in those individuals with chronic,
  neurological back pain, when administered in
  doses lower than those prescribed for depression.
  The researcher identifies 3 well-known,
  anti-depressive drugs which might have this
  positive side-effect, and labels them Drug A,
  Drug B and Drug C. The researcher then recruits a
  group of 60 individuals with a similar level of
  back pain and randomly assigns them to one of
  three groups - Drug A, Drug B or Drug C treatment
  groups - and prescribes the relevant drug for a 4
  week period. At the end of the 4 week period, the
  researcher asks the participants to rate their
  back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. The
  researcher wishes to compare the levels of pain
  experienced by the different groups at the end of
  the drug treatment period.
• Kruskal-Wallis test

8
Identify the appropriate statistic

• A researcher studied the relation between
  psychotherapists degree of empathy and their
  patients satisfaction with therapy

9
Identify the appropriate statistic

• A researcher studied the relation between
  psychotherapists degree of empathy and their
  patients satisfaction with therapy
• Correlation

10
Identify the appropriate statistic

• A researcher wants to examine whether music (no
  music", "classical music" and "dance music) has
  an effect on the perceived psychological effort
  required to perform an exercise session. The
  researcher recruited 12 runners who each ran
  three times on a treadmill for 30 minutes. For
  consistency, the treadmill speed was the same for
  all three runs. In a random order, each subject
  ran (a) listening to no music at all (b)
  listening to classical music and (c) listening
  to dance music. At the end of each run, subjects
  were asked to record how hard the running session
  felt on a scale of 1 to 10, with 1 being easy and
  10 extremely hard

11
Identify the appropriate statistic

• A researcher wants to examine whether music (no
  music", "classical music" and "dance music) has
  an effect on the perceived psychological effort
  required to perform an exercise session. The
  researcher recruited 12 runners who each ran
  three times on a treadmill for 30 minutes. For
  consistency, the treadmill speed was the same for
  all three runs. In a random order, each subject
  ran (a) listening to no music at all (b)
  listening to classical music and (c) listening
  to dance music. At the end of each run, subjects
  were asked to record how hard the running session
  felt on a scale of 1 to 10, with 1 being easy and
  10 extremely hard
• Friedman test

12
Identify the appropriate statistic

• A director of a small psychotherapy clinic is
  wondering whether there is any difference in the
  use of the clinic during different seasons o fthe
  year. Last year, there were 28 new clients in the
  winter, 33 in the spring, 16 in the summer, and
  52 in the fall. On the basis of last years data,
  should the director conclude that seasons makes a
  difference?

13
Identify the appropriate statistic

• A director of a small psychotherapy clinic is
  wondering whether there is any difference in the
  use of the clinic during different seasons o fthe
  year. Last year, there were 28 new clients in the
  winter, 33 in the spring, 16 in the summer, and
  52 in the fall. On the basis of last years data,
  should the director conclude that seasons makes a
  difference?
• Chi-square goodness of fit

14
Identify the appropriate statistic

• A pain researcher is interested in finding
  methods to reduce lower back pain in individuals
  without having to use drugs. The researcher
  thinks that having acupuncture in the lower back
  might reduce back pain. To investigate this, the
  researcher recruits 25 participants to their
  study. At the beginning of the study, the
  researcher asks the participants to rate their
  back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. After 4
  weeks of twice weekly acupuncture the
  participants are asked again to indicate their
  level of back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. The
  researcher wishes to understand whether the
  participants' pain levels changed after they had
  undergone the acupuncture

15
Identify the appropriate statistic

• A pain researcher is interested in finding
  methods to reduce lower back pain in individuals
  without having to use drugs. The researcher
  thinks that having acupuncture in the lower back
  might reduce back pain. To investigate this, the
  researcher recruits 25 participants to their
  study. At the beginning of the study, the
  researcher asks the participants to rate their
  back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. After 4
  weeks of twice weekly acupuncture the
  participants are asked again to indicate their
  level of back pain on a scale of 1 to 10, with 10
  indicating the greatest level of pain. The
  researcher wishes to understand whether the
  participants' pain levels changed after they had
  undergone the acupuncture
• Wilcoxon signed-rank test

16
Identify the appropriate statistic

• Researchers mailed a survey to a random sample of
  physicians. Half were offered 1 if they would
  return the questionnaire this was the
  experimental group) the other half served as a
  control group. The point of the study was to see
  if even a small incentive would increase the
  return rate for physicians surveys

17
Identify the appropriate statistic

• Researchers mailed a survey to a random sample of
  physicians. Half were offered 1 if they would
  return the questionnaire this was the
  experimental group) the other half served as a
  control group. The point of the study was to see
  if even a small incentive would increase the
  return rate for physicians surveys
• Chi-square tests of independence

18
Identify the appropriate statistic

• Van Prooijen and colleagues (2004) carried out a
  series of studies focusing on the effect of
  belongingness and being able to voice ones
  opinion about a decision on a persons
  satisfaction with the decision making process.
  The researchers measured procedural satisfaction
  by asking the students to rate how satisfied they
  were with the way they were treated by the other
  people on their team.

19
Identify the appropriate statistic

• Van Prooijen and colleagues (2004) carried out a
  series of studies focusing on the effect of
  belongingness and being able to voice ones
  opinion about a decision on a persons
  satisfaction with the decision making process.
  The researchers measured procedural satisfaction
  by asking the students to rate how satisfied they
  were with the way they were treated by the other
  people on their team.
• Factorial ANOVA

20
Identify the appropriate statistic

• The effectiveness of advertising for two rival
  products (Brand X and Y) was carried out at a
  local shopping centre. Participants were shown
  ads for two brands of coffee, which they then
  rated on the overall likelihood of them buying
  the product (out of 10, with 10 being definitely
  going to buy the product). Half of the
  participants gave ratings for one of the
  products, the other half gave ratings for the
  other product

21
Identify the appropriate statistic

• The effectiveness of advertising for two rival
  products (Brand X and Y) was carried out at a
  local shopping centre. Participants were shown
  ads for two brands of coffee, which they then
  rated on the overall likelihood of them buying
  the product (out of 10, with 10 being definitely
  going to buy the product). Half of the
  participants gave ratings for one of the
  products, the other half gave ratings for the
  other product
• Mann-Whitney test

22
Some humour

• http//www.youtube.com/watch?vJS9GmU5hr5w