These are the means and standard deviations for samples of building heights
in two different cities.
City A
Mean: 120 ft
Standard deviation: 20 ft
City B
Mean: 240 ft
Standard deviation: 12 ft
Select the two true statements.
D
A. City A's heights are more spread out than city B's heights.
B. City A's heights are less spread out than city B's heights.
c. City A has a lower average height than city B.
D. City A has a greater average height than city B.

A & C

A- City A’s heights are more spread out than city B’s heights.

C- City A has a lower average height than city B.

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.