Answer:
This is an observational study based on a stratified sample.
Step-by-step explanation:
This study aimed to check which clean-up/drying up method after handwashing was more effective; that is, do dryers eliminate more germs than paper towels.
It involved 100 people that took part in the study. The 100 of them contaminated their hands and were instructed to wash their hands with soap and water for 15 seconds before the participants are randomly grouped into two strata; one stratum/group (consisting of 50 participants) that dries their hands with a dryer and another (also consisting of 50 participants) that dry their hands with paper towels.
An observational study is one in which data is collected only by monitoring the events of the study. The conductor of the study in no way tries to intervene or control any of the variables being studied. No control, no tweaking of factors, just observe and record data.
An observational study based on a stratified sample is an observational study that uses the stratified sampling method to carry out its objectives. It randomly puts each of the participants being observed into groups or strata. Each group of randomly assigned participants are then required to run the test for one of the variables being compared.
This is exactly what the study in the question describes. This is why this study is undoubtedly an observational study based on a stratified sample.
Hope this Helps!!!
101 is the correct answer for 75+26
Answer:
Shorter piece length is 18 inches
Step-by-step explanation:
Let's marked first piece with x and second with y
x + y = 42
Given ratio is x : y = 3 : 4
From this proportion we get
x = 3 c and y = 4 c where c is coefficient of proportionality
when we replace this in initial equation we get
3 c + 4 c = 42 => 7 c = 42 => c = 42/7 = 6 c = 6
x = 3 · 6 = 18 inches and z = 4 · 6 = 24 inches
shorter piece is x = 18 inches
God with you!!!
