Sam was given a bag of 100 red and blue marbles. He believes that half of the marbles are red. To test his hypothesis, Sam draws a marble from the bag without looking, records its color, and then returns it to the bag. He repeats this process 49 times. If Sam picks 35 blue and 15 red marbles, which conclusion is accurate?

The ratio of blue marbles to red marbles is 35:15. To test his hypothesis in the best way, he should make sure that the total number of marbles he draws is 100. In other words, both sides of the ratio added together should equal 100. Right now, both sides equal 50 (35 + 15 = 50). To get to 100, double both sides of the ratio. Now, the ratio is 70:30. Based on the 50 marbles Sam drew, there are 70 blue marbles and 30 red marbles, meaning Sam's hypothesis is incorrect, and there are more blue marbles than red.

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.