A researcher wanted to check whether marriage causes people to become more responsible. Specifically, he was interested to know if marriage causes people to become more careful drivers. He went over the files of all car accidents that occurred in the past
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33 years in his state, and he calculated how many accidents out of the total number of accidents were caused by married people. Then, he compared his results with the actual percentage of married people in his state.
What type of statistical study did the researcher use?

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below. trans typ./ check no. date description of transaction payment/ debit deposit/ credit (+) balance 1,200 00 324 10/6 miller's food market 45.87 45 87 groceries 1,154 13 325 10/7 cyber center computer outlet 218.59 218 59 monitor 935 54 326 10/9 sandy's beauty salon 30.00 30 00 haircut and styling 900 59 deposit 10/10 paycheck 621.33 621 33 1,621 92 evaluate leslie's check register. a. leslie did a good job. everything is correct. b. the final balance is wrong; she did not add everything correctly. c. leslie should have written debit instead of deposit for the transaction type. d. leslie switched the debit and credit columns.