The FTSE 100 opened slightly lower on Friday morning following a strong rise the day before, as investors showed caution ahead of some pivotal economic data due out across the Pond later today.Financial trader Shavaz Dhalla from Spreadex said that investors are nervous about taking on too much risk ahead of the "market-moving US non-farm report" due out at 13:30 London time.Dhalla said: "The current US president as well as candidate for the presidential position will also be keenly eyeing the jobs figure. The consensus for the change in the number of employed people is 123,000. "However, a figure which comes in below expectations will not only prove damaging for investors' confidence in the global recovery but could act as sufficient ammunition for the leading presidential candidate to launch an offensive on the failures of the current US president's measures to stimulate growth."FTSE 100: Admiral and Meggitt disappoint with Q3 results; RBS subduedCar insurance firm Admiral dropped after seeing a 2% decrease in third-quarter turnover. "Little has changed since the half year. The UK car insurance market is cyclical and we are in the softer part of the cycle with premium rates coming down," said Chief Executive Henry Engelhardt. Aerospace, defence and energy components group Meggitt was unwanted after saying that organic revenues were flat year-on-year and revenue growth will be in the mid-single digits in 2013.Banking giant RBS was little changed after reporting a statutory loss before tax of £1.26bn for the three months to September 30th after taking a £1.46bn charge in own-credit adjustments and a £400m bill for PPI redress. Investec maintained its 'sell' rating for the stock this morning, saying that it had expected a loss of £1.0bn.Oil giant Tullow was a high riser after JPMorgan Cazenove upgraded its stance on the shares to 'overweight'. In contrast, engineering giant Weir was under the weather after Jefferies cut its rating to 'hold' and supermarket group Morrisons fell after Morgan Stanley downgraded the stock to 'underweight'.FTSE 250: Bumi gained on appointment of Rothschild GroupMining group Bumi advanced after saying it has appointed Rothschild Goup as its financial adviser with immediate effect to evaluate the proposal received from Long Haul Holdings. Hotels group Millennium & Copthorne fell despite seeing RevPAR rise 2.6% in the third quarter, with London enjoying an Olympic boost.Hikma Pharmaceuticals dropped after saying that it has opted to halt commercial production of generic drugs at Eatontown facility in the US until mid-January while it gets to grips with compliance issues raised by the Food & Drug Administration (FDA).Bwin.party digital entertainment, the world's largest listed online gaming company, fell after seeing revenues slip in the third quarter with several factors to blame, including a better regulation and the weak economic environment in Europe.FTSE 100 - RisersAberdeen Asset Management (ADN) 341.90p +2.06%Tullow Oil (TLW) 1,430.00p +1.63%Schroders (SDR) 1,573.00p +1.35%International Consolidated Airlines Group SA (CDI) (IAG) 165.40p +1.29%IMI (IMI) 988.00p +1.13%Rio Tinto (RIO) 3,199.00p +1.06%Land Securities Group (LAND) 818.50p +0.92%Burberry Group (BRBY) 1,225.00p +0.82%CRH (CRH) 1,184.00p +0.77%BHP Billiton (BLT) 2,023.50p +0.72%FTSE 100 - FallersAdmiral Group (ADM) 1,084.00p -5.08%Pennon Group (PNN) 704.00p -1.88%Croda International (CRDA) 2,137.00p -1.61%GlaxoSmithKline (GSK) 1,366.00p -1.55%Weir Group (WEIR) 1,768.00p -1.45%Morrison (Wm) Supermarkets (MRW) 263.80p -1.38%Royal Bank of Scotland Group (RBS) 283.90p -1.15%Marks & Spencer Group (MKS) 391.40p -1.11%National Grid (NG.) 704.50p -0.91%Standard Life (SL.) 297.70p -0.90%FTSE 250 - RisersBumi (BUMI) 267.00p +7.53%Perform Group (PER) 410.00p +4.06%Dixons Retail (DXNS) 24.23p +3.64%Chemring Group (CHG) 268.60p +3.07%New World Resources A Shares (NWR) 268.90p +2.67%Ferrexpo (FXPO) 225.50p +2.59%BBA Aviation (BBA) 208.90p +2.55%Carpetright (CPR) 716.00p +2.51%Daejan Holdings (DJAN) 2,925.00p +2.45%COLT Group SA (COLT) 111.40p +2.20%FTSE 250 - FallersHikma Pharmaceuticals (HIK) 726.50p -3.65%Centamin (DI) (CEY) 64.95p -3.20%Millennium & Copthorne Hotels (MLC) 501.00p -2.05%Balfour Beatty (BBY) 314.40p -2.00%Computacenter (CCC) 362.00p -1.44%Halfords Group (HFD) 352.10p -1.32%Cable & Wireless Communications (CWC) 37.51p -1.29%Telecom Plus (TEP) 840.00p -1.23%WH Smith (SMWH) 625.50p -1.11%Home Retail Group (HOME) 117.20p -1.10%BC