A car manufacturer claims that its family-size cars, when equipped with a type of shock absorber, can withstand a head-on shock at a speed of 10mph, with a repair cost of no more than $ 100. A sample of six cars, examined by an independent research office, revealed an average repair cost of $ 150 per car. The standard deviation was $ 30. Assume that the distribution of repair costs is approximately normal. Is there sufficient evidence to reject the company's claim at the 1% significance level?