To test out reaction, I take a copy of the book to an ultra-Orthodox Jewish study centre, where I meet a 22-year-old man in signature black hat and beard.

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My father used to take these out of the television set in the 1950s and '60s down to the local supermarket to test them and replace them.

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Eight out of 10 of the 1, 300 people who opted to take part in the survey did not agree with the test, it says.

BBC: Education & Family

McLaren have a big package of new parts to fit to the car overnight to try out on Saturday, when Jenson Button will take over from Hamilton, who drives again on the final day of the test, Sunday.

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The take-away was that a strategy may play out on paper, but the only way to truly test the validity of your product is to put it in front of customers.

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