Sanitary Bathroom
Habits: Men &
Women
Background:
Hand Washing with Soap:
•Single most effective behavior to reduce
spread of infectious diseases
•In United States: infectious diseases =
leading cause of death
Recent Study:
•Sampled the hands of commuters using
public transportation:
•¼
of people had FECAL matter
on hands
Background:
Studies on Hand Washing Behavior:
Wireless sensors measuring for 32 days:
65% WOMEN, 33% MEN
1996 Observational study:
74% WOMEN, 61% MEN
2000 Observational, 5 cities in U.S:
75% WOMEN, 58% MEN
2004: Observation on college campus:
85% WOMEN, 69% MEN
Background:
More about the 2004 College Study:
410 Students Observed
•Of those that washed their hands, only
64% used soap
•Only
10%
of hand washers washed hands for
longer than 15 seconds
•
69%
of those who washed hands washed for
1-6 seconds
Background:
Study conducted during SARS outbreak:
97% Women 95% Men washed hands
Survey on Hand Washing:
•95% of respondents reported hand
washing in public restrooms
•Hand washing = socially desirable
(over-reported in surveys)
Data Collection:
Observational Study: In Public Restrooms
•Observed:
132 MEN
121 WOMEN
•Locations:
Briarwood mall:
Ann Arbor, MI
Quality 16 movie theater:
Ann Arbor, MI
RiverTown Crossings mall:
Grandville, MI
Hartsfield-Jackson Atlanta
Int’l Airport: Atlanta, GA
•Recorded:
If hands were washed
(with or without soap)
Time spent washing hands
Total time spent in bathroom
•Variables:
1.
WASH HANDS
= whether or not subject washed hands (with or without soap)
2. TIME WASH
= seconds spent washing hands (contact with soap or water)
3. TOTAL TIME
= total time in minutes spent in the actual restroom
•Research Questions:
1. Do more females wash their hands in a public restroom than males?
2. Do females wash their hands for a longer period of time than males in
public restrooms?
3. Do females spend more time in the public bathrooms than males?
Power Analysis:
POWER: 80%
SIGNIFICANCE: 0.05
TEST 1:
(compare proportions)
HYPOTHESES: 1-Sided
TEST 2:
TEST 3:
(compare means)
(compare means)
•Parameter: 15% diff.
•Parameter: 2 sec. diff
•Parameter: 0.5 min. diff
•NEED: 134 each gender
•NEED: 20 each gender
•NEED: 20 each gender
•SAMPLE: 121 Females
132 Males
•SAMPLE: 29 Females
38 Males
•SAMPLE: 27 Females
42 Males
Relationship 1:
Question:
Is there a higher proportion of females who wash their
hands after using a public restroom than males?
Null Hypothesis:
The same proportion of males and females wash
their hands after using public restrooms
Alternative Hypothesis:
A higher proportion of females than males wash
their hands after using public restrooms
Variables Compared:
Gender and Handwashing (both categorical)
Cross Tabulation: Compare Proportions
Collection 1
Washed
No
Female
Gender
Male
Column Summary
S1 = count
S2 = row Proportion•
Row
Summary
Yes
6
115
121
4.95868
95.0413
100
62
70
132
46.9697
53.0303
100
68
185
253
26.8775
73.1225
100
At Least
Five of
Each
Response
Variable:
Yes
Proportion
Wash: Female
95.04%
Sample Size Female: 121
Proportion
Wash: Male
53.03%
Sample Size Male: 132
In our sample, FEMALES washed hands more
often than males.
Traditional Test P-value:
<0.0001 < .05
Conclusion Relationship 1:
1. P-Value 0.003 is less than significance level
of 0.05  REJECT NULL HYPOTHESIS
***it is unlikely that the difference in
proportions observed occurred by chance!!!
2. Evidence supports the alternative hypothesis:
***in this sample, the proportion of females who wash their hands
after using a public restroom is greater than the proportion of males
3. Within the population of Americans, adult females did indeed
wash their hands more often than males after using a public
restroom.
Relationship 2:
Question:
Do females wash their hands after using public
restrooms for a longer period of time than males?
Null Hypothesis:
Females and males wash their hands the same
amount of time after using public restrooms
Alternative Hypothesis:
Females wash their hands for a longer amount of
time than males after using public restrooms
Variables Compared:
Gender and Time Spent Washing (one
categorical and one quantitative)
BOX PLOT: COMPARE MEANS
SKEWNESS:
NONE
TIME
SPENT
HANDWASHING
(sec)
OUTLIERS:
ONE
GENDER
Mean seconds MALES:
Mean seconds FEMALES:
5.4 sec
7.8 sec
Sample Size Males: 29
Sample Size Females: 38
In our sample, FEMALES washed hands in restroom for
2.4 seconds longer, on average
Traditional Test P-value:
0.0034 < 0.05
Conclusion Relationship 2:
1. P-Value 0.003 is less than significance level of
0.05  REJECT NULL HYPOTHESIS
***it is unlikely that the difference in means
observed occurred by chance!!!
2.
Evidence supports the alternative hypothesis:
***in this sample, the difference in means found (females wash hands an
average of 2.4 seconds longer) was significant
3. Within the population of Americans, adult females did indeed
spend more seconds washing their hands after using a public restroom
Relationship 3:
Question:
Do females spend more time in public
restrooms than males?
Null Hypothesis:
Females and males spend the same amount of
time in public restrooms
Alternative Hypothesis:
Females spend more time than males in public
restrooms
Variables Compared:
Gender and Time Spent in Restroom (one
categorical and one quantitative)
BOX PLOT: COMPARE MEANS
SKEWNESS:
Slight in males,
nothing major
TIME
SPENT
IN
BATHROOM
(min)
OUTLIERS:
ZERO
GENDER
Mean minutes MALES:
1.03 min
Sample Size Males: 42
Mean minutes FEMALES:
2.73 min
Sample Size Females: 27
In our sample, FEMALES spent 1.7 more
minutes in the bathroom, on average.
Traditional Test P-value:
<0.00001 < 0.05
Conclusion Relationship 3:
1. P-Value <0.00001 is less than significance
level of 0.05 
REJECT NULL HYPOTHESIS
***it is unlikely that the difference in means
observed occurred by chance!!!
2.
Evidence supports the alternative hypothesis:
***in this sample, the difference in means found (females spend 1.7 more minutes
in public restrooms than males) was significant
3. Within the population of Americans, adult females did indeed
spend more minutes public restrooms
Final Summary:
Test 1:
Test 2:
•Proportion of males & females
who wash hands in public restroom
•P-value < 0.001
•REJECT NULL HYPOTHESIS
•Females proportion: 42% higher
•Time spent washing hands
•P-value: 0.003
•REJECT NULL HYPOTHESIS
•Females: 2.4 seconds longer,
on average, in our sample
Test 3:
•Time spent in public restrooms
•P-value < 0.001
•REJECT NULL HYPOTHESIS
•Females spend 1.7 minutes longer,
on average, in our sample
Study Limitations:
• Lindsay & Christine created a SOCIAL PRESSURE during data
collection (stood near the subjects as they washed hands)
•Difficult to MEASURE PRECICESLY how long subjects washed
hands
•Couldn’t tell a difference between when subjects were ALONE and
when they were being watched
•LOCATIONS: 3 public places in Michigan,
and one place in Atlanta: NOT very
representative of the whole country
Resources for Background Information:
Judah, G., Schmidt, W., Michie, S., Granger, S., & Curtis, V. Experimental
Pretesting of Hand-Washing Interventions in a Natural Setting. 2009.
American Journal of Public healh, 99(2), 405-411.
Monk-Turner, E., Edwards, D., Broadstone, J., Hummel, R., Lewis, S., & Wilson, D.
Another Look at Hand-Washing Behavior. 2005. Social Behavior and
Personality, 33(7), 629-634.