An epidemiologist wishes to study the factors which might contribute to heart disease. They ask doctors to provide biometric data on patients recently diagnosed with heart disease as well as data on patients who have not been diagnosed with heart disease. Is this an example of an observational study or an experiment? What are some possible sources of error? State at least two.

step-by-step explanation:

you divide the denominator by the numerator on both sides and if the quotients are equal then the fractions are equivalent

25

step-by-step explanation:

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.