Find x, round your answer to the nearest tenth. Please help.
1 answer:
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Answer:
a) The expected number of smokers in a random sample of 140 students from this university is 16.8 smokers.
b) No, it is unlikely that smoking habits and waking up early to go to the gym on Saturday are independent.
Step-by-step explanation:
To calculate the expected numbers of smokers in a sample with size n=140 and proportion p=12%, we use the expected value of the binomial distribution:
The expected number of smokers in a random sample of 140 students from this university is 16.8 smokers.
If we take a sample at the opening of the gym, the sample is not expected to be representative of the population of the students. Most of the students that go to the gym usually have healthy habits, so the proportions of smokers is expected to be lower than the average of the university population.
Answer:
Matrix multiplication is not conmutative
Step-by-step explanation:
The matrix multiplication can be performed if the number of columns of the first matrix is equal to the number of rows of the second matrix
Let A with dimension mxn and B with dimension nxp represent two matrix
The multiplication of A by B is a matrix C with dimension mxp, but the multiplication of B by A is can't be calculated because the number of columns of B is not the number of rows of A. Therefore, you can notice that is not conmutative in general.
But even if the multiplication of AB and BA is defined (For example if A and B are squared matrix of 2x2) the multiplication is not necessary conmutative.
The matrix multiplication result is a matrix which entries are given by dot product of the corresponding row of the first matrix and the corresponding column of the second matrix:
Notice that in general, the result is not the same. It could be the same for very specific values of the elements of each matrix.