Three different toys are stored in a warehouse. There are 15 000 toys in total and the number of each is shown in the table.
|Kinds of Stones||Bears||Dolls||Cars|
|Number of Stones||2 000||6 000||7 000|
A stratified sample of all the toys is taken and 420 cars are selected. Calculate the total number of toys in the sample.
A class in a school contains 38 students. At the end of the school year 28 of the students passed mathematics, 32 passed science, and 26 passed both science and mathematics. If a student is chosen at random from the class, what is the probability that they failed science?
Which type of random sample should be used to determine the subject preferences of a group of 400 students given the ratio of males to females is ?
Which type of random sample can be used to study the level of qualifications in a society divided into lower class, middle class and upper class?
In what sort of sampling does the researcher divide the population into separate groups called strata, then draw a probability sample from each group?
Which type of random sample is used for selecting a sample from one strata of society?
Which of the following choices would define a random experiment?
Which of the following is an outcome of a random experiment?